Consider the following C program: void swap_by_ref (int *u, int *v) { int temp; temp = *u; *u = *v; *V = temp; return; } main ( ) { int u = 9, v = 6; swap_by_ref (&u, &v); } (a) Write a complete extended BNF grammar that will derive the above program as a valid string of tokens. Start symbol is (Program). (b) State all the syntactic categories and terminal symbols in your grammar.