A 60kg man stands on a spring scales in a lift. At some instant. He finds that the scale reading has changed from 60kg to 50 kg for a while and then comes back to original mark. What should be concluded?
A. The lift was in constant motion upwards
B. The lift was in constant motion downwards
C. The lift while in constant motion upwards, is stopped suddenly
D. The lift while in constant motion downwards, is suddenly stopped
