@greeklearn "The answer" would always be "την απάντηση" and vice versa. The indefinite article, though, is used slightly differently in greek than in english. If I say "Δεν έχω μία απάντηση", "μία" is probably an arithmetic (implying I have more than one answers).
Can anybody explain why "απάντηση" here means "an answer" and not "the answer"?
Νo article -> indefinite form translation in English. Κeep in mind that IN MOST CASES it sounds more natural if you don't use the indefinite article ένας/μία/ένα.