One Reason That Diseconomies of Scale Arise Is Because

One reason that diseconomies of scale arise is because:

A) the short-run average total cost curve rises when marginal product is increasing.
B) of the difficulties involved in managing and coordinating a large business enterprise.
C) firms must be large both absolutely and relative to the market to employ the most efficient productive techniques available.
D) beyond some point marginal product declines as additional units of a variable resource (labor) are added to a fixed resource (capital) .