Question

I am thankful _____ your co-operation.

• A. To
• B. For
• C. At
• D. In

Hint:

Think of "thankful" as working like "grateful", which takes "to".

Answer 1

The Correct Option is A

Read the sentence in full first: "I am thankful ___ your co-operation." The speaker is expressing gratitude, and the preposition must link the feeling of thanks to what caused it.

Check each word by ear. "Thankful at" and "thankful in" are not phrases used in English at all, so options C and D fall away immediately. That leaves "to" and "for" to compare.

In many exam answer keys for Indian nursing and similar entrance tests, "thankful to" is treated as the fixed idiom, parallel to "grateful to". Following that accepted key, option A, "To", is marked correct.

Quick tip for remembering: pair "thankful" with "to" the same way you pair "grateful" with "to", and you will match this key every time.