Correct Answer - B
`f:N to N, f(n)=2n+3.`
Here, the range of the function is `{5,6,7, …} " or " N-{1,2,3,4},`
which is a subset of N (co-domain).
Hence, function is into.
Also, it is clear that `f(n)` is one-one or injective.
Hence, `f(n)` is injective only.