Something is wrong with one of these singular plural sets. Identify it:

Correct option is D

The correct option is (D) Criterion-criterion.

• Explanation: The singular of "criterion" is criterion and its correct plural form is criteria, not "criterion" again. This makes option (D) incorrect.

• Correct form:

Singular: criterion

Plural: criteria

• Hindi Explanation: "Criterion" का बहुवचन "criteria" होता है, न कि "criterion" ही दोबारा।

• Meanings of other options:

▪ (a) Maximum-maxims – Correct; "maximum" and "maxims" are unrelated words, but they are spelled correctly.

Hindi: Maximum (अधिकतम), Maxims (कहावतें, सिद्धांत).

▪ (b) Phenomenon-phenomena – Correct; "phenomenon" (singular) and "phenomena" (plural) are accurate.

Hindi: घटना - घटनाएँ.

▪ (c) Nucleus-nuclei – Correct; "nucleus" (singular) and "nuclei" (plural) are correct forms.

Hindi: नाभिक - नाभिकों.