detailed solution

Correct option is D

Option a “ Foxen ” is non-standard, dialectical plural of the noun fox. The present plural form is foxes. thus, option a is incorrect. 
Option b “ foxene ” is incorrect as there is no analogous word in the English language. 
Option c “ foxine ” is Wrong also. There is no analogous word in the English language. 
Option d “ harridan ” is the feminine form of the noun fox. before it was “ fixen ”. therefore, option d is the correct answer.