The alkali metals form salt-like hydrides by the direct synthesis at elevated temperature. The thermal stability of these hydrides decreases in which of the following orders?

Question

( A ) CsH>RbH>KH>NaH>LiH
( B ) KH>NaH>LiH>CsH>RbH
( C ) NaH>LiH>KH>RbH>CsH
( D ) LiH>NaH>KH>RbH>CsH