In each of the questions given below four words are given in bold. These four words may or may not be in their correct position. The sentence is then followed by options with the correct combination of words that should replace each other in order to make the sentence grammatically and contextually correct. Find the correct combination of the words that should interchange. If the sentence is correct as it is then, select option “No interchange required” as your choice.

The spinster (A) carefully loosened her thread (B) from the spin (C) and began to spool (D) it into a masterpiece.

The correct combination of words that should interchange is C-D.

Let us analyze the contextual and grammatical meaning of the highlighted words in the given sentence:

"The spinster (A) carefully loosened her thread (B) from the spin (C) and began to spool (D) it into a masterpiece."

1. Spinster (A): Refers to an unmarried woman (historically one who spins thread). This is contextually appropriate as the subject doing the action.

2. Thread (B): Refers to the strand of fiber being spun or used, which makes context and grammatical sense in this position.

3. Spin (C): Here, "spin" is used as a noun, but in the context of holding thread on a device, the correct word is a "spool" (a cylindrical device on which thread is wound).

4. Spool (D): Here, "spool" is used as a verb, but following "began to", the action of twisting or turning thread into a creation is referred to as "spin" (to spin into a masterpiece).

By swapping C (spin) and D (spool), the sentence becomes grammatically correct and contextually meaningful:

"The spinster (A) carefully loosened her thread (B) from the spool (C) and began to spin (D) it into a masterpiece."

Therefore, the words that need to be interchanged are C-D.