A DPDT switch can control _____.

A Double Pole Double Throw (DPDT) switch is designed to control two separate circuits simultaneously. Each pole can connect to two different terminals, allowing for a change in the electrical path. This capability means that a DPDT switch can control two circuits, and each circuit can have two different states or outputs because of the double throw feature.

In practical terms, each of the two poles of the switch can either connect to its corresponding terminal for one circuit (the 'normally closed' position) or switch to another terminal (the 'normally open' position). Therefore, the configuration allows for controlling two circuits in an either/or manner, effectively making it able to manage four different connections (two for each circuit). However, since it is controlling two discrete circuits with the potential for alternate configurations, one can assert it effectively operates as controlling two distinct circuits at once.

The other options imply the switch can manage more than two circuits simultaneously, which is incorrect given the functional definition of a DPDT switch. Each additional circuit control would require additional poles and throws, which this switch does not have. Thus, the correct interpretation of a DPDT switch clearly aligns with the capacity to control two circuits.