Final answer:
The correct statement that will change the last value of p to 75 is p[99] = 75. This is because arrays are zero-indexed.
Step-by-step explanation:
The correct statement that will change the last value of p to 75 is p[99] = 75. This is because arrays are zero-indexed, so p[99] refers to the last element in the array. The other statements, p[100] = 75, s[99] = 75, and s[100] = 75, would result in errors or out-of-bounds access.