Using the Abbreviations Listed Below, What Is the Market Share

Using the abbreviations listed below, what is the market share variance?
AMS = actual market share
BMS = budgeted market share
BCM = budgeted contribution margin per unit
ACM = actual contribution margin per unit
ATM = actual total market
BTM = budgeted total market

A) (ATM − BTM) (BMS) (ACM)
B) (ATM − BTM) (BMS) (BCM)
C) (AMS −BMS) (ATM) (ACM)
D) (AMS − BMS) (ATM) (BCM)