An example of a simple mechanism that can be modeled by a state machine is a coin$-$operated turnstile. A turnstile, used to control access to subways and amusement park rides, is a gate with three rotating arms at waist height, one across the entryway. Initially the arms are locked, blocking the entry, preventing patrons from passing through. Depositing a coin in a slot on the turnstile unlocks the arms, allowing a single customer to push through. After the customer passes through, the arms are locked again until another coin is inserted.

The state machine for a turnstile is shown below:

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The above turnstile needs to be updated to add a bypass function. An administrator may use a key to turn on or off the bypass function. Once the bypass is turned on$,$ the turnstile is always unlocked without needing of depositing coins. Once it is turned off, the turnstile returns to its normal operations. If necessary, draw a new state machine on a piece of paper, and answer

Which of the following statements is true about the updated turnstile?

In its state machine, each state has a total of three transitions.

Its state machine has four states.

In its state machine, each state has a total of four transitions.

Its state machine has three states.