A series of studies conducted in restaurants indicates that when people dine in groups, they tend to ...

A series of studies conducted in restaurants indicates that when people dine in groups, they tend to order ____. This finding can be explained by the fact that ____.
 
  a. a variety of different itemsmore variety than expected by chance, people tend to conform to one another's orders
  b. a variety of different itemsmore variety than expected by chance, people don't like to order the same items that others are ordering
  c. a very narrow selection of itemsmore narrow than expected by chance, people tend to conform to one another's orders
  d. a very narrow selection of itemsmore narrow than expected by chance, people don't like to order the same items that others are ordering