University of Cinciminnati assignment question

Question

Which of the following runs fastest (assume page size is 4096 bytes)?

a) int i, j, npages = 10000;
char *arr;
arr = (char*)malloc(4096*(npages+1));
for (i=0 ; i < npages ; i++) {
for (j=0 ; j < 4096 ; j++) {
arr[i+j] += 1;
}
}

b) int i, j, npages = 10000;
char *arr;
arr = (char*)malloc(4096*(npages+1));
for (i=0 ; i < npages*4096 ; i++) arr[i] += 1;

c) int i, j, npages = 10000;
char *arr;
arr = (char*)malloc(4096*(npages+1));
for (j=0 ; j < 4096 ; j++) {
for (i=0 ; i < npages ; i++) {
arr[i+j] += 1;
}
}

Comments

reference: http://gauss.ececs.uc.edu/Courses/c4029/exams/Fall2012/c4029_fall_1_12_sol.pdf