I think it might be C) to show that he can make untamed noises as well
They were looking for the mythical 7 cities of gold which they never found, but they did find the grand canyon and several other famous landmarks
A. 5×20
x=100
check
100/5=20
20=20
b. 15=30/2
×2. ×2
30=30.
check.
30/2=15
15=15
Hope this helps..