Answer:
Explanation:
A catalyst is something that hastens a reaction, but does not really take part in it. So the candy tablets looks like a catalyst, but you have put this under English, so I'm not exactly sure what the answer should be.
It isn't D.
It could be C.
I don't think it can be B. That's not a catalyst in the true sense of the word. The bubbles show that the gasses have been released. But it is not catalytic.
I'll stick with A, but I wouldn't object to C.
