1 has become extremely popular recently?

*: “Trampolining is taking off in a big way, and some new centres have as many as 150 trampolines.”

=> B

2 requires you to do two things at once?

*: “It's easier to do both activities when you're running and talking at the same time”

=> C

3 has made an existing form of exercise more extreme?

*: “Reformer Pilates is a much more intense form of Pilates.”

=> A

4 gives the wrong impression to the observer?

*: “At first, it looks quite easy, but towards the end of the session, your thighs will be crying out for mercy.”

=> A

5 tires you out after a very short time?

*: “You'd be surprised by how exhausted you are after only a few minutes bouncing.”

=> B

6 can be particularly painful?

*: “but towards the end of the session, your thighs will be crying out for mercy.”

=> A