Given that the mass of the planet is the same as the mass of the earth and the radius of the planet is two times that of the earth.
The mass is a fundamental property of a matter and it does not change.
The weight is the force acting on an object due to gravity.
From Newton's law of gravitation, the gravitational force is directly proportional to the product of the mass of the objects and inversely proportional to the square of the distance between them.
Thus,
Where W is the weight and r is the radius of the planet.
Thus, when the radius is doubled,
Thus the weight will decrease by a factor of 4.
Thus, the correct answer is option B.