In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Q: Problem: bruce and anne can clean their house in 4 hours working together at their respective constant rates . if anne ' s speed were doubled , they could clean their house in 3 hours working at their respective rates . how many e hours does it currently take anne to clean the house on her own ?
Options: a ) 6 , b ) 7 , c ) 8 , d ) 12 , e ) 14
A:
d