India lost 11.73 lakh man days
to strikes in 2017, and according to estimates made by the Labor Bureau, they cost the nation 550 crore rupees.Option Elimination -
A. to strikes in 2017, and according to estimates made by the Labor Bureau, they cost the nation 550 crore rupees - "they" can refer to "man-days" or strikes." Ambiguous.
B. to strikes in 2017, which according to estimates made by the Labor Bureau, cost the nation 550 crore rupees - "which" can refer to "strikes." Though it violates the "touch rule," it's the best among the lot. A flexible modifier, "a loss that....." would have been better, but I guess that will not make it challenging.
C. in strikes in 2017, and according to estimates made by the Labor Bureau, it cost the nation 550 crore rupees - "it" referring to what? No.
D. in strikes in 2017, so as to cost the nation 550 crore rupees, according to estimates by the labor bureau - "so as to" means in order to. Illogical.
E. to strikes in 2017, which according to estimates made by the Labor Bureau, thus costs the nation 550 crore rupees - "costs" singular. Neither goes with "strikes" or man-days." Wrong