In each of the following questions, a sentence is given with four highlighted words. These words may or may not be placed in their correct positions. Choose the option that represents the correct pair of words that should be interchanged to make the sentence grammatically correct and contextually meaningful.

The blazing (A) sun cast scorching (B) rays across (C) the desert, exhausting (D) the weary travelers on their journey.

The correct option is No replacement needed.

Let us analyze the sentence to check whether the highlighted words are placed in their correct positions:

1. blazing (A): The adjective "blazing" means extremely hot or bright. It appropriately describes the "sun".
2. scorching (B): The adjective "scorching" means very hot or burning. It logically modifies the noun "rays".
3. across (C): The preposition "across" accurately indicates the movement or spread of rays over "the desert".
4. exhausting (D): The participle "exhausting" means making someone feel extremely tired. It correctly expresses the effect of the heat on "the weary travelers".

Since all the highlighted words are contextually meaningful and grammatically correct in their original positions, no word interchange is required.