**Explanation:**

When the centrifugal switch in the starting winding of a single-phase induction motor fails to open, it means that the switch fails to disconnect the starting winding from the power supply once the motor reaches a certain speed. This can lead to several issues, with the most significant impact being on the starting winding itself.

Here is a detailed explanation of what happens when the centrifugal switch fails to open:

**1. Continuous operation of the starting winding:**
- The starting winding is designed to provide the necessary phase shift to create a rotating magnetic field for starting the motor.
- Normally, the centrifugal switch opens when the motor reaches a certain speed, disconnecting the starting winding from the power supply.
- However, when the switch fails to open, the starting winding remains connected to the power supply throughout the motor's operation.

**2. Overheating of the starting winding:**
- The starting winding is not designed for continuous operation and is typically made of thinner wire with limited thermal capacity.
- When the starting winding remains energized during the motor's operation, it experiences continuous current flow, which leads to excessive heating.
- The continuous heating of the starting winding can cause insulation breakdown, leading to short circuits, or even complete failure of the winding.

**3. Increased power consumption:**
- The starting winding draws a significant amount of current during motor startup to create the necessary torque.
- When the switch fails to open, the starting winding continues to draw current from the power supply, resulting in increased power consumption.
- The increased power consumption can lead to higher electricity bills and overload the power supply system.

**4. Reduced motor efficiency:**
- The continuous operation of the starting winding not only increases power consumption but also affects the motor's overall efficiency.
- The starting winding, being designed for high torque and not continuous operation, can introduce additional losses and reduce the motor's overall efficiency.
- The reduced efficiency can lead to increased operating costs and decreased performance.

Therefore, the correct answer is option 'B': The starting winding will overheat. When the centrifugal switch fails to open, the starting winding remains energized during motor operation, causing excessive heating and potential failure of the winding.