The correct answer is option 'D', which states that all of the given options are examples of the Law of inertia. Let's discuss each option and understand how they relate to the Law of inertia.

1. Starting in throwing the hammer:
- When you start throwing the hammer, you need to apply a force to accelerate it. However, according to Newton's first law of motion, also known as the Law of inertia, an object at rest tends to stay at rest unless acted upon by an external force. Therefore, before you apply the force, the hammer will remain stationary due to its inertia.

2. Starting in sprinting:
- Similarly, when you start sprinting, your body initially remains at rest or in a stationary position. According to the Law of inertia, your body will resist any changes in its state of motion. So, when you apply a force to your body by pushing off the ground, you overcome the inertia and start moving.

3. Starting in rowing:
- In rowing, when you start rowing, the boat initially remains stationary in the water. According to the Law of inertia, the boat will resist any changes in its state of motion. So, when you apply a force by pushing against the oars, you overcome the boat's inertia and start moving.

The Law of inertia, formulated by Sir Isaac Newton, states that an object will remain at rest or continue moving in a straight line at a constant speed unless acted upon by an external force. In other words, objects tend to maintain their state of motion unless acted upon by an unbalanced force.

Conclusion:
In each of the given examples (throwing the hammer, sprinting, and rowing), the initial state of rest or stationary position is overcome by applying an external force to initiate motion. This aligns with the Law of inertia, which states that objects resist changes in their state of motion. Therefore, option 'D' is the correct answer as all the given options demonstrate the Law of inertia.