In preparation for the cold winter months, it was the usual custom for prehistoric people to gather and preserve, with smoke or by salting it, as much meat that they could during the summer.
(a) It was the usual custom for prehistoric people to gather and preserve, with smoke or by salting it, as much meat that they could during the summer.
(b) prehistoric people usually gathered as much meat as they could during the summer, preserving it either by smoking or salting
(C) It was the usual custom of prehistoric people to gather and preserve, either with smoke or by salting, as much meat that they could during the summer
(d) prehistoric people had the usual custom of gathering and preserving as much meat, either by smoking or salting it, as they could during the summer
(e) It was usually that prehistoric people would gather and preserve as much meat as they could, which was either smoked or salted during the summer
Choice B -is the answer. However, doesnt the "it" after the comma have a vague antecedent.. Cant it refer to preserving the summer.
Choice D- though wordier isnt it the better answer?