Three large plates are arranged as shown. How much charge will flow through the key K if it is closed?
(A) 5Q/3
(B) 4Q/3
(C) 3Q/2
(D) None of these

It appears that you've described a situation involving three large plates arranged in a certain configuration with a key K. To determine how much charge will flow through the key K when it is closed, we need more information about the arrangement of the plates and any initial conditions (such as charges on the plates or the presence of a battery).

The amount of charge that flows through a circuit or a key when it is closed depends on various factors, including the potential difference (voltage) across the circuit and the resistance of the circuit. Without this additional information, we cannot calculate the exact amount of charge that will flow through the key K.

Please provide more details about the configuration and any other relevant information, and I'll do my best to assist you further.