help on this C++ question

Assuming the following declarations, find the mistakes in the statements below.

struct A { int m1[2]; int m2; } 

struct B { A a1; A* a2; int m3; } 

A a; 

B b[2]; 

a. b[0].a2 = a;

b. b[1].m2 = 42;

c. b[2].a2 = new A;

d. b[0].a1.m1 = 42;

e. b[1].a2->m2 = 42;