Read the Following Scenario and Answer the Question Below

Read the following scenario and answer the question below.
After meeting with their instructor, Pablo and Johanna know that they need to change their experimental design. They contact a local puppy farm and arrange to do their study with 3- month- old litters of pups from four Irish setters, for a total of 24 puppies consisting of 12 females and 12 males.
-Pablo and Johanna should probably run the experiment _________

A) for several months, weighing and measuring the pups twice every day
B) for several months, weighing and measuring the pups before and after
C) for at least three years, weighing and measuring the pups every week
D) for several months, weighing and measuring the pups every week
E) for one month, weighing and measuring the pups before and after