A sensor that stops a machine if a door is opened is an example of a(n) __ Barrier interlock Guard interlock Electrical interlock Mecharical interlock Flag Reset

## Step 1<br />The problem is asking us to identify the type of sensor that stops a machine if a door is opened. This is a safety feature in many machines, especially those that operate at high speeds or have moving parts. The sensor in question is a type of interlock, which is a safety device that prevents the machine from operating under certain conditions.<br /><br />## Step 2<br />The options provided are different types of interlocks. The correct answer is the one that best fits the description of the sensor in question.<br /><br />## Step 3<br />The correct answer is "Guard interlock". This is because a guard interlock is a type of interlock that is used to prevent the machine from operating if a door or other guard is opened. This is done to ensure that the machine does not operate in an unsafe manner, which could lead to injury or damage.