X and Y are each Group 2 metals. Both X and Y make hydroxide compounds, but $X(\text{OH})_2$ dissolves in water more readily than $Y(\text{OH})_2$. When a piece of metal Y is added to cold water, the reaction is very slow, and only a few tiny hydrogen bubbles are visible. What could the identities of X and Y be?
- AX: barium, Y: magnesium
- BX: barium, Y: strontium
- CX: calcium, Y: strontium
- DX: magnesium, Y: calcium