A set of 10 new questions in each round. Question: ( 1 of 10 ) Catherine can finish a work in 100 days. Heather can finish the same work in 105 days while Diane can finish the work in 110 days. How long will it take to finish it if they work together? (A) 78.75 days (B) 68 626/661 days or 68.947 days (C) 105 days (D) 34 626/661 days or 34.947 days