In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

[Q]: Article: Sales Executive Pindan Labor Solutions is expanding and we require a sales executive. Working hours from Monday to Friday,12 months a year. However,some weekend work may be required. You will be assisting our team of consultants with business development. You can get a monthly income of $5,200.Essential requirements include previous sales experience,strong communication skills,high level of computer competency ,WA driver's license. For more information,please email stefan@tigerhospitality.com or phone 0452 236 541. Martial Arts Trainer GoKanRyu Karate has a number of positions available for people who have an interest in the martial arts. The position will involve training new students on working days. An expected first year income of $45,000.Excellent people skills and previous experience are essential. Own car and license required. Please contact Tim Hort on 0285 371 464 or kyle@hospitalio.com for further information. Workshop Manager Located in Wongan Hills WA,Beckman Machinery wants a service/workshop manager to join our successful team. Your role will be to provide the best possible service to customers,Monday to Friday. You must have trade certificate,excellent communication and computer skills. Knowledge of agricultural products is essential. You can get at least $50,000 in your first year. Please call Stuart 0427 777 105 or email stuart@boekemans.com.au if any further information is needed. Farmhand A general farmhand is required to work on a farm located 40kms from Condobolin.A driver's license is essential. Duties include:sheep,cattle work;cropping & irrigation .Weekends off,except during sowing and harvest periods.$39,000 a year. If you are interested in farm work,please email diane.moisis@cwcc.nsw.edu.au or call 0167 327 047 for detailed information.
Answer: A sales executive.
[A]: Of the four positions,which offers the top yearly income?

[Q]: Article: What if we could replace oil with a fuel which produced no pollution and which everybody had equal access to? The good news is that we can. In fact, we are swimming in it--- literally. Hydrogen is one of the building blocks of the universe. Our own sun is basically a big, dense cloud of the stuff. And hydrogen can be used to create electricity for power, heat and light. The problem is that hydrogen is everywhere and nowhere at the same time. It does not exist as a material on its own, but is always part of something else. So it has to be separated before it can be used. Most commercial hydrogen in use now is created from natural gas. As oil will start to run out in around the year 2030, it makes sense to produce as much hydrogen as possible as soon as we can. But natural gas supplies will also begin to run out soon after. Another source is needed. Researchers are now using electricity to make water into hydrogen. Companies are working on the problem in their own areas. The first commercial hydrogen "fuel cells" for computers and mobile phones have already come on to the market. Auto companies have also invested over US $2 billion in the production of hydrogen fuelled cars. The nations of a hydrogen fuelled planet would not fight over energy recourses. There would be a great reduction in pollution. The only by-product of creating hydrogen is pure drinking water--- something that is very scarce in many parts of the world. But that is not where the good news ends. Once the costs of producing hydrogen have been brought down, it will possibly provide power for a third of the Earth's population that has no electricity. And electricity creates wealth. In South Africa over the last decade there has been a large programme of electrification. Thanks to the programme, people do not have to spend their days looking firewood to burn for heat. And with electric light, they can work long into the night. Some scientists see radical changes in the way the human race co-operates. Hydrogen creates electricity, and is also created by _ . With dual use fuel cells, everyone who consumes energy could also produce it. Late at night, a man drives home in London and connects his car into the "world-wide hydrogen web," which it supplies with electricity. A few hours later, a man in Beijing uses that electricity to power the hydrogen cell in his car. Hydrogen could be the first democratic energy source. Like all dreams of the future, it seems very far away. But the threat of war and terrorism in the Middle East has made governments and businesses more aware of the need to end oil dependency and spend more time and money on hydrogen resource. So maybe the threat of war is not a completely bad thing for the future of the human race.
Answer: It has to be separated from other materials.
[A]: What is the problem with using hydrogen as energy?

[Q]: Article: Invisible ink has fascinated kids for generations. You might think that it would be difficult to make, but it's not. All you'll need for this experient is some milk; some white paper; a clean cotton swab or small, clean paintbrush; the kitchen stove; and help from an adult. The most difficult part of this mini-project is choosing the message that you'll write with your invisible ink. Maybe you'll want to pretend that you're a spy on a secret mission, writing messages that would lead to big, big trouble if they were discovered. Choose your words carefully. All you need to do is, using the brush of cotton swab, write your message with milk on the paper. Don't use a lot of milk and soak the paper. Use just enough to make a thin coating. Once you've finished writing, ask the adult who's helping you to turn on the kitchen stove to a low heat. Very carefully, using kitchen mitts ,hold the paper about a foot above the warm burner. If you don't see results, you may have to make the burner a little hotter. Do not, however, hold the paper low over the burner. As the paper heats up, your message will become brown and you'll be able to see what was written. You want to know why? It's because chemical compounds in the milk have a low burning point. When the paper gets warm, those compounds will heat up and trun brown, while the paper will be unaffected. You also can try this experiment with other liquids, such as orange juice, lemon juice, vinegar, and apple juice. Just be sure to follow all safety rules and have an adult around to help you.
Answer: Making Invisible Ink
[A]:
What is probably the best title for the passage?