Consider the following tasks related to basic types of functions.
a. Part 1: (i) Define an injective function and a surjective function.
b. Part 2: (ii) Let A be a finite set with ∣A∣=n. Explain why every injective function f:A→A must necessarily be bijective.
c. Part 3: (iii) State whether the conclusion in part (ii) remains true when A is an infinite set, giving a brief justification or a counter-example.