Answer:
Option C.
Step-by-step explanation:
Two beauticians Lydia and Jackie are working on your hair.
Lydia takes the time to complete the work = 2 hours
Per hour work done by Lydia = 1/2
Jackie complete the work = 1 hour
In one hour total work done by both Jackie and Lydia together = 
therefore, time taken by both to complete the work will be =
= 
Option C. two thirds is the correct option.