Which of the following motors has the highest total impulse?

The motor with the highest total impulse in this context is the K100. Total impulse is a measure of the total energy produced by a rocket motor and is expressed in Newton-seconds (Ns). When comparing the choices, each motor designation indicates a range of total impulse based on the letter and number associated with it.

The letter indicates the motor's size, with 'H,' 'I,' and 'K' representing increasing impulse classes. The number indicates the specific motor in that class, and a higher number within the same letter represents a higher thrust. In this case, the K class motors provide more total impulse than any of the H or I class motors listed.

To summarize, the K100 motor has the highest total impulse owing to its designation, which indicates it can produce more thrust compared to the H100, H200, or I100 motors.