Explanation:

- Horsepower is a unit of power.

- It was originally designed to compare steam engines to the power output of horses.

- 1 horsepower (hp) is approximately equal to 746 watts.

- Option:1 - 746 represents the correct conversion of horsepower to watts.

- Option:2 - 764 is incorrect; this value is too high.

- Option:3 - 647 is also incorrect; it is too low.

- Option:4 - 674 isn't accurate as well; again, it is too low.