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.

There are some careers (A) where you can’t afford (B) to make even the most disastrous (C) mistake without infinitesimal (D) consequences.

To determine the correct interchange of words, let us analyze the context and grammar of the sentence:

The sentence is: "There are some careers (A) where you can’t afford (B) to make even the most disastrous (C) mistake without infinitesimal (D) consequences."

First, let's look at the words in their current positions:
- careers (A): Fits contextually. There are indeed some fields of work (careers) where precision is critical.
- afford (B): Fits grammatically and contextually in the phrase "can't afford to make..." which means one cannot allow or risk making a mistake.
- disastrous (C): Describes a mistake. While a "disastrous mistake" makes sense on its own, let's examine it in combination with the rest of the sentence. The phrase "without [D] consequences" is key. If a mistake is "disastrous" (extremely bad/harmful), it would naturally have large, severe consequences, not "infinitesimal" (extremely small/negligible) ones.
- infinitesimal (D): Means extremely small. In the current structure, "without infinitesimal consequences" implies that even a disastrous mistake would only have tiny consequences, which is logical nonsense because a disastrous mistake inherently leads to huge consequences. Conversely, if we swap C and D, the sentence reads: "...to make even the most infinitesimal (D) mistake without disastrous (C) consequences."

Let's evaluate the sentence with the swap of C and D:
"There are some careers where you can’t afford to make even the most infinitesimal (D) mistake without disastrous (C) consequences."
This version is perfectly logical: it means that in certain careers, even the tiniest, most microscopic mistake (infinitesimal) will inevitably lead to terrible, severe outcomes (disastrous consequences).

Therefore, the words in positions C and D must be interchanged to make the sentence contextually correct.

Thus, the correct option is C-D.