To determine the fraction of a clockwise revolution the hour hand of a clock turns through when it goes from 12 to 3, we need to understand the movement of the hour hand and the total number of divisions in a full revolution.

- The movement of the hour hand: The hour hand of a clock completes one full revolution in 12 hours. This means that it takes 12 hours for the hour hand to go from one hour mark to the same hour mark again.

- Total number of divisions in a full revolution: A clock is divided into 12 hours, marking each hour with a number. Therefore, there are 12 divisions in a full revolution of the clock.

Now, let's calculate the fraction of a revolution the hour hand turns through when it goes from 12 to 3.

Step 1: Determine the number of hours it takes to go from 12 to 3.
Going from 12 to 3 means moving 3 hours ahead. Therefore, it takes 3 hours for the hour hand to reach the 3 mark.

Step 2: Calculate the fraction of a revolution.
Since the hour hand takes 12 hours to complete one full revolution, and it takes 3 hours to go from 12 to 3, we can calculate the fraction of a revolution as follows:

Fraction of a revolution = (Number of hours taken)/(Total hours for a full revolution)
= 3/12
= 1/4

Therefore, the fraction of a clockwise revolution the hour hand turns through when it goes from 12 to 3 is 1/4, which corresponds to option D.