the answer will be c cause av node is also auto excitable but it generated less number of potential per minute hence the rate will different

The impulse generated by the sinoatrial (SA) node is responsible for initiating the electrical activity in the heart, which leads to the contraction of the cardiac muscles. If this impulse fails to be transmitted in both ventricles, it can have several possible outcomes.

Potential outcomes when the impulse fails to be transmitted in both ventricles:

1. Only the atria contract, ventricles do not:
- This scenario occurs when the impulse is blocked or delayed at the atrioventricular (AV) node, which is the electrical bridge between the atria and ventricles.
- The atria continue to contract, but the ventricles do not receive the electrical signal, resulting in their failure to contract.
- This condition is known as heart block, and it can have different degrees of severity depending on the extent of the blockage.

2. Only the ventricles contract:
- In rare instances, a separate pacemaker in the ventricles may take over and generate its own electrical impulse.
- This can lead to ventricular contraction without the involvement of the atria.
- However, this situation is not sustainable in the long term, as the coordinated contraction of both atria and ventricles is essential for efficient pumping of blood.

3. Atrial and ventricular contractions occur at different rates:
- If the impulse is delayed or blocked at different levels within the electrical conduction system, it can result in the atria and ventricles contracting at different rates.
- This can lead to an irregular heartbeat, known as arrhythmia, where the atria and ventricles are not synchronized in their contractions.

4. The entire heart stops contracting:
- In severe cases, if the impulse fails to be transmitted in both ventricles and no alternative pacemakers take over, the heart can stop contracting altogether.
- This situation is known as cardiac arrest and is a medical emergency requiring immediate intervention, such as cardiopulmonary resuscitation (CPR) and defibrillation.

In summary, if the impulse generated by the SA node fails to be transmitted in both ventricles, it can lead to various outcomes ranging from partial contraction to complete cessation of heart activity. The specific outcome depends on the location and severity of the blockage or failure in the electrical conduction system of the heart.