(a) Give an example of two functions f: A→B and g: B-C such that f is both 1-1 and onto but gof is neither 1-1 nor onto (note: g of means g compose f). You may choose the sets A, B, C as you wish. (It is a good strategy to choose them as simple as possible.) (b) Given two functions f: A→B and g: B-C where ƒ and g are both onto. Prove that go also onto. of is