What is the output of the following code?

int main() {

int x = 1; int y = 1;

while ( y < 4 ) {

cout << (x * y) << " ";

y = y + 1;

x = x + 2;

}

return 0;

}

Select one:

a. 1 4 9

b. 1 6

c. 1 6 15

d. 1 6 15 28