percentage of SI

What percentage of simple interest per annum did Anu pay to Deepika?

I. Anu borrowed Rs. 8000 from Deepika for four years.

II. Anu returned Rs. 8800 to Deepika at the end of two years and settled the loan.

A. I alone sufficient while II alone not sufficient to answer
B. II alone sufficient while I alone not sufficient to answer
C. Either I or II alone sufficient to answer
D. Both I and II are not sufficient to answer
E. Both I and II are necessary to answer

Watch this space for answer in a week.