3. A mapping \( f: n \rightarrow N \), where \( N \) is the set of natural numbers is defined as \( f(n)=\left\{\begin{array}{cc}n^{2}, & \text { for } n \text { odd } \\ 2 n+1, & \text { for } n \text { even }\end{array}\right. \) for \( n \in N \). Then, \( f \) is
(a) surjective but not iniective
(b) injective but not surjective
(c) bijective
(d) neither injective nor surjective
