Correct Answer - b,c
If elevator is slowing down acceleration `= -a`
If elevator is speeding up acceleration `=+a`
going up and slowing down
`R - mg = m (-a)`
`R = m (g -a)`
(b) going up and speeding up
`:. R - mg = ma R = m (g + a)`
(c) going down and slowing down
`mg - R = m (-a)` or `R = m (g + a)`
(d) going down and speeding up
`mg - R = ma` or `R = m (g -a)` .