JEE Main Physics question

If a body of mass m is carried by a lift moving with an upward acceleration a, then the forces acting on the body are (i) the reaction R on the floor of the lift, upwards, and (ii) the weight mg of the body, acting vertically downwards. The equation of motion is given by

• (A)R = mg − ma
• (B)R = mg + maCorrect
• (C)R = ma − mg
• (D)R = mg × ma