What type of switch can crowd an electrical circuit when constantly held?

A pushbutton switch is designed to momentarily complete a circuit when pressed. When held down, it maintains a connection that allows current to flow continuously, effectively 'crowding' the circuit by keeping it in an active state for as long as it is pressed. This behavior is fundamental to its operation, as it is typically used to activate or deactivate a circuit temporarily.

In contrast, a toggle switch is designed for manual switching between two states (on/off) and does not require constant pressure to maintain its position. A float switch operates differently, responding to changes in liquid levels, and a relay functions as an electrically operated switch that opens or closes circuits in response to an input signal. These options do not maintain a circuit when held and are structured around different operational principles, illustrating why a pushbutton switch is the correct answer in this context.