Answer:
Im not completely sure about the answer, but A and C are Wrong
Explanation:
This is because the snail growing its shell is a physical change. For the shell of a snail to grow, the snail must consume Calcium to grow its shell. And would grow it just like how we grow our fingernails!
Rust forming on a bicycle frame is an example of a chemical change. This is caused by metal being exposed to oxygen. Just like when you leave your bike outside in the rain, it'll get rusty!