Which of the following statements is correct?
选项：

A:Strategic situations are more likely to arise when the number of decision-makers is very large rather than very small.;
B:Strategic situations are more likely to arise in monopolistically competitive markets than in oligopolistic markets.;
C:Game theory is useful in understanding certain business decisions, but it is not really applicable to ordinary games such as chess or tic-tac-toe.;
D:Game theory is not necessary for understanding competitive or monopoly markets.