(A)(p∨q)⇒(p∧q)<br/><imgsrc="/api/proxy−image?url=httpsp ⇔ q
<br/>(B)(p∧q)⇒(p∨q)istautologybecause(p∧q)issubset of \left(p ∨ q\right)
\left(C\right) \left(p ∨ q\right)
⇔(p∧q)
which is same as
p⇔q \left(D\right)\left(p ∨ q\right)
∨(p∧q)
which is same as
p⇔q