If a mutation has a visible effect at $26\backslash$deg C but no visible effect at $20\backslash$deg C$,$ then $20\backslash$deg C is the $\_\_\_\_\_\_\_$ temperature and $26\backslash$deg C is the $\_\_\_\_\_\_\_$ temperature.

A$.$restrictive; permissive

B$.$permissive; conditional

C$.$conditional; restrictive

D$.$restrictive; conditional

E$.$permissive; restrictive