 
<translate> Ọrụ ha atọ rụrụ n'otu ụbọchị = 1/7 + 1/8 + 1/12 = 59/168 Ọnụ ọgụgụ nke ụbọchị achọrọ = 168/59 = 2 50/59 ụbọchị. N'ihi ya, azịza ya bụ (A). <eng> Work done by all three of them in one day = 1/7 + 1/8 + 1/12 = 59/168
The number of days required = 168/59 = 2 50/59 days.
Thus, the answer is (A). 