da business

Useful stuff to be able to answer the following question:
forward vertical integration = i buy the business of my client[if i'm a beer company i would buy a logistics company of beer trucks])
backward vertical integration = i buy the business of my provider [provider of hops]).
Q--U--E--S--T--I--O--N:
a) forward vertical integration of the beer sector occurs more often than backward vertical integration of customers.
b) backward vertical integration of customers occurs more often than forward vertical integration of the beer sector.
c) the backward vertical integration occurs with all types of customers. (dont thinks so)
d) the forward vertical integration allows the beer industry to reduce significantly the bargaining power of customers.

ONLY ONE TRUE STATEMENT . THANK YOU VERY, VERY, VERY MUCH FOR YOUR HELP!!! BEST REGARDS, SARAH (petitgirl17@hotmail.com) if you dont mind, i need to know how you got the answers: references, statistics... because i need to be sure they are accurate. Thank you so much!!!!