Hello, i need help finding the time complexity(big0) for n..(java)

a)

for (int a = 0; a < n; a = a + C)

for (int b = 0; b < 10; b++)

s[a] += b * s[a];

b)

for (int a = 1; a < n; a = a * C)

for (int j = 0; j < a; j++)

s[a] += j * s[a];

c)

for (int i = 1; i < n; i = i * 2)

for (int j = 0; j < n; j++)

s[i] += j * s[i];

Thanks for your help!