Bags with wide straps are preferred to carry heavy loads. The reason for this is :

Correct option is C

The correct answer is Increase in area of contact reduces pressure exerted.
Pressure:
Pressure refers to the force applied perpendicular to the surface of an object per unit area over which that force is distributed. The SI unit is the Pascal (pa).
The formula for pressure is:
P=F/A
• The pressure is dependent on the area over which the force is acting.
• The pressure can be decreased or increased without any change in the force.
• The force applied is constant if the surface becomes smaller, the pressure increases, and vice versa.
• The weight of a bag is the force with which it is pulled towards the earth.
• The shoulder carries a bag that exerts a force that is equal to its weight.
• So, using a large and wide strap of bags ensures that the same weight (Force) is transferred to the shoulder through the large area of the strap.
• For the same force, pressure x 1 / area. Hence, as the area increases the pressure produced is less.