明朝仁宣时期，朝廷内制的敕、诏、册、表等专由内阁负责，内阁权力迅速膨胀，其地位已经超过六部。对其理解最准确的是                                         

A．内阁成为行 * * 力的中心

B．内阁权力已经完全合法化

C．内阁成为决策中心

D．内阁权力比以往扩大

It _____ have been Tom that parked the car here, as he is the only one with a car. [ ]

A. may

B. can

C. must

D. should