A person deposited 400 Rs. for 2 years, 550 Rs. for 4 years and 1200 Rs. for 6 years. He received the total simple interest of 1020 Rs. The rate of interest per annum is :

[A]5%

[B]10%

[C]15%

[D]20%

**10%**

Let the rate of interest be R per cent per annum.

Hence option [B] is correct answer.