The mass of a body measured by a physical balance in a lift at rest is found to be m. If the lift is going up with an acceleration a, its mass will be measured as

• A.  \[m\left( 1-\frac{a}{g} \right)\]         
• B.         \[\left( 1+\frac{a}{g} \right)\]
• C.  \[m\]                      
• D.         Zero