Find Big-O for algo / codes using step count. Define best case and worst case wherever applicable?

c) for (i = 0, length = 1; i < n-1; i++) {

for (i1 = i2 = k = i; k < n-1 && a[k] < a[k+1]; k++, i2++)

if ( length < i2 - i1 + 1)

length = i2 - i1 + 1; }

d) for (cnt2 = 0, i = 1; i <= n; i++)

for (j = 1; j <= i; j++)

cnt2++;

e.) for (cnt3 = 0, i = 1; i <= n; i *= 2)

for (j = 1; j <= n; j++)

cnt3++;

f) for (cnt4 = 0, i = 1; i <= n; i *= 2)

for (j = 1; j <= i; j++)

cnt4++;