(a) $\exists x R(x) \vee \forall y[\sim S(y)]$
∃xR(x) : there exists atleast a number such that x-7=2 so x=9 that means this statement is True
∀y[∼S(y)] = ∀y[y $\leqslant$ 9] : all y are less then equal to 9 : False
so T ∨ F = True
(b) P(x,y) : x>y
$\forall x \exists y P(x,y)$ : For every x there is at least one less y , so for domain is real number then this is True
(c) $\forall x \exists y(P(x,y) \cup Q(x,y)) $
$\forall x \exists y((x>y) OR (x\leqslant y)) : True$
So Ans : D