4. A student wants to measure the length of a rod by using a venier caliper, which of the follow- ing formula is suitable for the measurement?
(a) M.S.R+ (V.C.D x L.C)
(b) P.S.R-C.S.Rx L.C
(c) M.S.R- (V.C.D x L.C)
(d) P.S.R + C.S.Rx L.C

please answer fast​