Do tell me the ways you think of _____ the problem as soon as possible. [ ]

A. to solve

B. solving

C. solve

D. being solved

对静电现象的认识，下列说法中正确的是 [ ]

A．自然界只存在两种电荷

B．同种电荷互相吸引，异种电荷互相排斥

C．摩擦起电创造了电荷

D．在各种带电微粒中，电子所带电荷量的大小是最大的