The metal with which hydrogen reacts to form metal hydride is:

The correct option is B $Ca$
A hydride is the anion of hydrogen, $H^{-}$, it is a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties.

Ag and H does not form hydride while calcium form calcium hydride, Calcium hydride ($Ca{H}_2$ ). This grey powder (white if pure, which is rare) reacts vigorously with water liberating hydrogen gas. $Ca{H}_2$is thus used as a drying agent, i.e. a desiccant. $Ca{H}_2$ is a saline hydride, meaning that its structure is salt-like. The alkali metals and the alkaline earth metals all form saline hydrides.