The correct answer is C. 981.
A dyne is a unit of force in the CGS system of units. It is defined as the force required to accelerate a mass of one gram at a rate of one centimeter per second squared.
One gram of weight is the force exerted by gravity on a mass of one gram. The acceleration due to gravity on Earth is approximately 9.81 meters per second squared. Therefore, the force of gravity on one gram of mass is 9.81 dynes.
Option A is incorrect because 250 dynes is less than the force of gravity on one gram of mass.
Option B is incorrect because 375 dynes is also less than the force of gravity on one gram of mass.
Option D is incorrect because 900 dynes is greater than the force of gravity on one gram of mass.