If the temperature is 100 °F, pressure altitude is 4,000 ft, and weight is 3,200 lb with calm winds, what is the ground roll required for takeoff over a 50-foot obstacle?

The correct answer is based on the relationship between environmental conditions, aircraft weight, and performance data, which collectively influences the required takeoff distance over an obstacle.

At a temperature of 100 °F, density altitude will be significantly greater than the stated pressure altitude of 4,000 feet due to the warm temperature. Higher density altitude reduces engine performance, propeller efficiency, and lift generated by the wings, which increases the distance required for takeoff.

Given a weight of 3,200 lbs, this adds another layer to the performance calculations. The heavier the aircraft, the longer the takeoff roll required, especially when overcoming obstacles.

The specific performance charts for the aircraft in question would outline the ground roll required under those conditions, incorporating both the temperature and weight factors. The calculation adjustments made from these charts for takeoff over a 50-foot obstacle ultimately lead to the required takeoff distance. In this scenario, the calculations show that the ground roll required aligns closely with the number given in option A, making it the most accurate choice.

This answer, therefore, reflects a comprehensive understanding of how temperature, altitude, weight, and obstacle clearance interact to affect aircraft performance during takeoff.