Q49

Consider the set of all functions $f:\{0,1, \dots,2014\} \to \{0,1,\dots, 2014\}$ such that $f\left(f\left(i\right)\right)=i$, for all $0 \leq i \leq 2014$. Consider the following statements: $P$. For each such function it must be the case that for every $i,f(i) = i$. $Q$. For each such function it must be the case that for some $i,f(i)=i$. $R$. Each function must be onto. Which one of the following is CORRECT?