2.For each of the following five program fragments, give an analysis of the running time using Big-Oh notation.

a.sum = 0;

for( i = 0; i < n; i++ )

sum++;

b.sum = 0;

for( i = 0; i < 2n; i++ )

sum++;

c.sum = 0;

for( i = 0; i < 2n; i++ )

for( j = 0; j < i; j++ )

sum++;

d.sum = 0;

for( i = 0; i < n²; i++)

for( j = 0; j < i; j++)

sum++;

e. sum = 0;

for( i = 0; i < n; i++)

for( j = 0; j < i*i; j++)

for( k = 0; k < j; k++)

sum++;