Question

Which of the following is/are function(s)?

• A.
• B.
• C.
• D.

Answer 1

Answer: (B), (D)

For given relation to be function, each element in domain $A$ should have only one image in co-domain $B$.
So, option $\left(b\right)$ and $\left(d\right)$ are function because every element of set $A$ has one and only one image in set $B$.