a ceramic or metal container in which metals or other substances may be melted or subjected to very high temperatures.
"the crucible tipped and the mold filled with liquid metal"
a situation of severe trial, or in which different elements interact, leading to the creation of something new.
"their relationship was forged in the crucible of war"
Metals are the type of elements that are most likely to form more than one type of ion, for instance iron can form the ion of Fe^2+ or Fe^3+.
I would say the first three. But I'm not 100% sure. I'm truly sorry if it's wrong
This would be c as for the amswer
