Many dog owners do not look or love their pets, but it is difficult fo

Correct Option D

Original sentence
Many dog owners do not look or love their pets, but it is difficult for authorities to know whether abuse is taking place.

A. or love their pets, but it is difficult for authorities to know whether abuse is taking place
Flaw:
- "look after" is correct phrase

B. after or love their pets, but it is difficult for authorities to know whether or not abuse is taking place
Flaw:
- "whether or not" is redundant
- When using the phrase "whether or not," the "or not" is often superfluous (i.e., not required). However, when "whether or not" means "regardless of whether,"

C. after or love their pets, but it is difficult for authorities to know if abuse is taking place
Flaw :
- "if" to introduce a condition, (Eg. if X, condition Y)
- "Whether" is used
1.) To present two alternatives (neither of which is a condition).
2.) After prepositions
3.) Before infinitive verbs starting "to" (e.g., whether to ask).
4.) When "whether" starts a clause that is the sentence subject or complement.

D. after or love their pets, but it is difficult for authorities to know whether abuse is taking place
- Correct

E. after or love their pets, but authorities find it difficult to know whether abuse is taking place or not
Flaw :
- Authority is replaced by "it"
- "or Not" is adding one more conditional, not required