Solution

Statement (a) is not legal because we cannot take the address of a constant value like $44$.

Statement (b) is legal because if $r$ is an integer variable, then &r gives its address and it can be stored in an integer pointer.

Statement (c) is not legal because &a gives address, but $P$ is declared as normal integer, not pointer.

Statement (d) is legal because if $a$ is an integer variable, then its value can be assigned to integer variable $P$.

So, legal statements are:

(b) and (d)