Fill in the blank with appropriate tense-
After I had eaten five apples, I _____ ill. (Feel)
a) Feel
b) Felt
c) Am feeling
d) None of these

Hint: Read the given phrase/sentence carefully. Try to make out the meaning of it and find the subject or the predicate or the main object of the sentence.

Complete answer:
The given sentence conveys that after when the speaker has eaten five apples, the speaker got ill. We have to use the correct tense form of the given word ‘feel'. Tenses are of three types – present, past, and future.
Now, let us examine all the given options to find out the correct option -
Option ‘a’ is Feel. It cannot be the correct answer as we want a present continuous tense in the given sentence. So, we will eliminate this option.
Option ‘b’ is Felt. It cannot be the correct option as it is in the past tense and cannot be the correct option. So, we will eliminate this option as well.
Option ‘c' is Am feeling. It is in the present continuous tense and can be used in the given blank. The speaker is still feeling ill, so it is the only appropriate option.
Option ‘d’ is None of these. We will choose this option only if all the other three options are incorrect or aren’t suitable for the given question.
As we have analyzed all the given options we can easily figure out the correct option. Here, the correct answer is – am feeling. Hence, option ‘c’ is the correct option.

Note:
The tenses have to be made out by reading the given sentence. The tenses are of three more types, simple, perfect, and continuous.