Volume Index in Marshall is ____________?

Volume Index in Marshall is ____________?

A. ∑Pn(Po + Pn)/∑Pn(Po + Pn)
B. ∑Pn(qo + qn)/∑Pn
C. ∑Pn(Po + Pn)/∑Pn(Po + Pn) x100
D. Non of these