Which line in the following program contains the header for the showDub function? 1 #include«iostream» 2 using namespace std; 4 void showDub (int); 6 int main 8 int x2 10 showDub (x): 11 cout << x << endl; 12 return 0: 13 14 15 void showDub (int num) 16 17 cout << (num * 2) << endl; 18 a. 4 b. 6 c. 10 d. 15 12. Which line in the following program contains a call to the showDub function? 1 #include 2 using namespace std 4 void showDub (int) 6 int main) int x = 2; showDub (x): return 0; 10 11 cout << x < endl: 12 13 14 15 void showDub (int num) 16 17 cout (num 2) s endl 18 a. 4 b. 6 c. 10 d. 15