I thnk ans should be C
coz :
a. Insuff x=2,y=3 is diff then if u put x=3,y=2

b.
If y > 7 . let y =8 ,x=3 then
x(y+1) = 27 odd
let y = 9 ,x=3
x(y+1) = 30 even


and if u take both prime and y>7 then it holds
x=2,y=9
x(y+1) =2*10 =20
x=2,y=11
x(y+1) = 24
Always even if y >7 & prime.

But ans is something else. I am wrong somwhere but dont know where.