Which passage is the best example of deductive reasoning

D is using deductive reasoning,

Explanation: deductive reasoning is when you figure something out using logic and using the information you already have, without asking someone.

The answer is letter D

Explanation:

   Deductive reasoning means having  true statements (also called premises) and reaching to a logical conclusions based on them. There is always a logical thought process, where you move from general ideas to more specific ones.

   Let's have a look at this example of deductive reasoning:

All apples are fruits. Pink Lady is a type of apple. Therefore, the Pink Lady is a fruit.

The first two sentences are the premises. From those two true statements, the logical conclusion that the Pink Lady apple is a fruit is reached.

   In the question, sentence D is an example of deductive reasoning. The first two statements are the true facts that we have (Everyone got an A in Mr. Kims's class and Casey is in that class). Therefore,  Casey is getting an A. There's no room for another conclusion.  You have reached a conclusion based on true statements.

1, 4, and 5 are all conflicts

the following what exactly?