A set of 10 new questions in each round. Question: ( 2 of 10 ) If Patricia can finish the work in 5 days and William can finish the same work in 9 days, then in how many days both can finish the work together? (A) 3 3/14 days or 3.214 days (B) 6 3/14 days or 6.214 days (C) 14 days (D) 7 days