Which of the Following Is True in Relation to Market

Which of the following is true in relation to market share and monopoly power?

A) Market share is rarely used as a test of monopoly power because it is difficult to determine.
B) A market share greater than 50% generally indicates monopoly power.
C) A market share between 50 and 75% is, in itself, inconclusive in determining monopoly power.
D) Market share is a common test for monopoly power because it is an easy, objective measurement for courts to determine.