Among the alkali earth metals, the tendency to react with other substances a) increases from bottom to top within the group. b) is shown by the ways they react with water. c) varies in an unpredictable way within the group. d) does not vary among the members of the group.

The answer would be letter A.Among the alkali earth metals, the tendency to react with other substances increases from bottom to top within the group. We know that when there is an increase of metallic property, there will also be an increase of reactivity. 

True.

Explanation:

An example is:

HCl + NaOH ---> NaCl + H2O.