In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D". 

[Q]: [header] How to prevent greasy hair [title] Shampoo properly. [step] Apply a small, quarter-sized amount of shampoo to your scalp and massage vigorously with your fingertips. Then, work the lather through your hair and rinse. <sep> (A) [title] Rub a dime-sized amount of baby oil in your palm. [step] Squirt a dime-sized amount of all-purpose baby oil into your palm and then use the back of a spoon to massage the lather into your hair. (B) Body wash will also work well to loosen the oil from your hair and prevent it from slacking off. Comb your fingers through your hair to ensure that all areas of your hair are clean. (C) [substeps] Whether you have wet or dry hair, lather the lather gently and never hold it in place for more than one second. [title] Consider bed-wetting your hair as often as you can. (D) Rinse hair thoroughly so no shampoo is left behind. Washing your hair should take about five minutes.
[A]: D


[Q]: [header] How to get rid of the whitefly [title] Vacuum the flies. [step] Use a small hand vacuum, or hold the furniture-cleaning nozzle of a standard vacuum cleaner. Walk around your infested plants and suck the pests from the undersides of the leaves and foliage. <sep> (A) This method is quick and straightforward, and it can remove whiteflies from all stages of the development cycle-from larvae to mature, plant-munching adults. Vacuuming is most effective as soon as you notice an infestation. (B) [substeps] Lice/hornets that have infested the insect where possible will probably cause an infestation when they have access to this species. Lice and hornets can be pregnant bees or even cobwetters. (C) [substeps] Once you've vacuumed up all of the insects, you can dismantle the insect and wash it off. Plant diseases like freeze burn-gas are very likely to have mites, fungus, or other biological problems with this insect. (D) [substeps] If possible, clean the potted plants as a habit to keep the insects away. [title] Tear off the hard outer leaves once the insects have died.
[A]: A


[Q]: [header] How to become an aerospace engineer [title] Develop sound math and science skills in high school. [step] Aerospace engineering requires advanced science and math skills. Take classes in chemistry, physics, algebra, calculus, and trigonometry in high school to get a head-start on developing the skills you'll need. <sep> (A) Some four-year colleges offer pre-schooling courses in engineering. Some high schools offer an all-family education program which focuses on automobile mechanics, mechanical engineering, and physics. (B) [substeps] You should be at least 18 years old when you begin your aerospace engineering career. You can get an an a in about five years. (C) [title] Speak with your teacher about whether engineer training is right for you. [step] If you need to grow intellectually, the best way to do so is to find a training location. (D) [substeps] Put your best effort into these classes so you can earn high marks. A high gpa will help you get into a good aerospace engineering program in college.
[A]:
D