The factored load at the limit state of collapse for DL + LL, DL + WL and DL + LL + WL combinations, according to IS: 456-2000 are respectively.
a) 1.2 DL + 1.2 LL, 1.5 DL + 1.5 DL, 1.5 DL + 1.5 LL + 1.5 WL
b) 1.5 DL + 1.5 LL, (0.9 or 1.5) DL + 1.5 WL, 1.2 DL + 1.2 LL + 1.2 WL (Ans)
c) 1.5 DL + 1.5 LL, 1.2 DL + 1.2 WL, 1.5 DL + 1.5 LL + 1.5 WL
d) (0.9 or 1.5) DL + 1.5 LL, 1.5 DL + 1.5 WL, 1.2 DL + 1.2 LL + 1.2 WL