Answer:
option A 50%
Step-by-step explanation:
Ability to roll the tongue is dominant to people who cannot. thus only one copy is needed for the trait to be expressed. Thus, a tongue roller could be XTXT, XTXt or XTY and a non could be XtXt and XtY.
Thus one can have the highest percentage of non-tongue roller to be 50% which is from a cross between a tongue roller male and a non tongue roller female.