Which of the following is a correct pair of singular and plural?

The correct answer is Option (4) → Hypothesis:Hypotheses

The correct pair of singular and plural is:

☀ Hypothesis:Hypotheses

Explanation for each option:

☀ Horse:Horse: This is incorrect. The singular form of "Horse" is "Horse," and the plural form is also "Horses."

☀ Stomach:Stomaches: This is incorrect. The correct plural form of "Stomach" is "Stomachs."

☀ Pony:Ponys: This is incorrect. The correct plural form of "Pony" is "Ponies."

☀ Hypothesis:Hypotheses: This is correct. The singular form of "Hypothesis" is "Hypothesis," and the plural form is "Hypotheses."