Calculate the commercial simple interest of:

a) L. 2,000.00 for 3 years at 0.75% per month.

b) L. 4,000.00 for 2 years, 3 months at 0.5% per month

c) L. 10,000.00 for 4 years at 5% semi-annual

d) L. 25,000.00 for 1 year, 3 months at 6% semi-annual