The following statement is wrong: () A. The resultant force of the athletes sliding in a straight line with constant inertia on the smooth ice is zero. B. After the skydiver leaves the cabin,

A, because athletes do uniform linear motion, the resultant force of far mobilization is zero;

B, because the paratroopers fall at a uniform speed, the kinetic energy of the paratroopers remains unchanged and the gravitational potential energy decreases, so the mechanical energy of the paratroopers decreases;

C, because the car is moving in the horizontal direction, and the direction of gravity is vertical downward, so the work done by gravity is zero;

D. Making the backpack strap wider is to reduce the stress by reducing the stress area.

So choose D.