Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Context: Marino finished the game with 29 out of 50 pass completions for 318 yards, 1 touchdown, and 2 interceptions. Clayton was the top receiver of the game, with 6 receptions for 92 yards. Walker returned 4 kickoffs for 93 yards and gained 15 yards on 2 punt returns. Nathan was the Dolphins leading rusher with 18 yards, while also catching 10 passes for 83 yards. Craig had 58 rushing yards, 77 receiving yards, and 3 touchdowns. He was the first player ever to score 3 touchdowns in a Super Bowl, and his 2 touchdown catches also tied a Super Bowl record. Tyler led San Francisco in rushing with 65 yards, and also caught 4 passes for 70 yards. Clark caught 6 passes for 77 yards. Board recorded 2 sacks. McLemore recorded 51 punt return yards, the second most in Super Bowl history. Sports Illustrated called 49ers defensive tackle Gary Johnson (American football) the Super Bowls "unofficial defensive MVP" after he recorded one sack, flushed Marino out of the passing pocket numerous times, and had four unassisted tackles. 
 Question: Who had a higher average of yards per caught pass, Clayton or Clark?
clayton

Context: 2008 will be remembered by us Chinese people as a year of sadness and happiness. May of the year sadly saw the Great Sichuan Earthquake, the worst earthquake in China over 30 years. It killed around 70,000 people. Tens of thousands were injured or went missing. However, to our delight, China also hosted its first Olympic games that summer in Beijing. It was a very successful games with a great opening ceremony. 43 new world records and 132 new Olympic records were made. And China came out first with 51 gold medals. 
 Question: How many gold medals did China win at the 2008 Beijing Olympic Games?
51.

Context: Inventors are always looking for ways to make our lives easier, greener and a whole lot more fun. Take a look at the following breakthroughs in science and technology. What in the world will inventors dream up next? Superhero Suit Have you ever dreamed of becoming a superhero? Dream no more. There's a real Iron Man suit, XOS 2, which instantly transforms the person wearing it. The suit provides the power to lift 200 pounds with ease and break slabs of wood with a single karate chop. It was designed to help the military with heavy lifting. One person in the suit could do the work of three soldiers. Up, Up and Away! It took him 30 years to develop it, and now Glen Martin's invention is ready to take off. The Martin Jetpack allows its operator to fly 8,000 feet into the air. Unfortunately, you can't soar through the skies too long. The jetpack holds only 30 minutes' worth of fuel. The aircraft will sell for $100,000. Hardworking Robot The EMIEW2 robot is the perfect office helper. Need a document delivered? No problem! It can also guide visitors to their destinations. The three-foot-tall robot can identify different human voices and respond to commands. One day, it may serve as a receptionist or a security guard. Green Machine Say goodbye to gasoline! The AirPod car runs on air power. That means this car won't pollute the environment. A high-pressure air tank can fill the car in minutes. The three-wheeler can travel about 130 miles between fill-ups. Beef Power All aboard the beef train! Amtrak's Heartland Flyer runs partly on fuel that is made from cow fat. The goal is to reduce carbon emissions by 10%. The train travels between Oklahoma City, Oklahoma, and Fort Worth, Texas. Robo-Guard EMILY is a robotic, four-foot-long buoy . She can swim through riptides at up to 24 miles per hour. Her inventor, Tony Mulligan, says that's 15 times as fast as human lifeguards! EMILY is powered by a tiny electric pump and operated by remote control. 
 Question: How many environment-friendly inventions are mentioned in the passage?

three.