How many persons opted both Mathematics and Biology?

strong >Read the following information and answer the questions that follow. There are six friends (Ranvir, David, Smith, Virender, Faizal and Anukalp) in a group. Each person can opt only three subjects out of the six subjects which are Physics, Chemistry, Biology, Mathematics, Accountancy, and Economics.
I. Ranvir, Smith and Anukalp opted Chemistry.
II. Virender did not opt Biology, but opted Physics.
III. Both David and Faizal opted Mathematics and Physics.
IV. Ranvir and Virender did not opt Mathematics and Economics, but they opted Accountancy.
V. Only two persons opted Economics.
VI. Only two persons opted Accountancy.
VII. Anukalp did not opt Accountancy, Physics and Economics.
VIII. Smith did not opt Biology and Physics, but he opted Economics.
IX. Ranveer and David opted Biology.