What happens when there is an open in the primary of a transformer?

When there is an open circuit in the primary winding of a transformer, it means that there is no complete path for current to flow. The transformer relies on the alternating current in the primary winding to create a magnetic field that induces a voltage in the secondary winding. Without the current flowing in the primary, there is no magnetic field generated, and as a result, there is no induced voltage in the secondary winding. This leads to the situation where the output voltage in the secondary is effectively prevented, making the statement regarding the prevention of output voltage in the secondary the correct response.