**Core Concept**
The question is testing the concept of cardiac motion and its phases, particularly during imaging techniques such as cardiac MRI or CT scans. Cardiac motion is a critical factor in cardiac imaging, as it affects the quality of the images obtained.

**Why the Correct Answer is Right**
The correct answer is during late diastole. This is because late diastole marks the period of minimum cardiac motion. During this phase, the heart is in a state of relaxation, and the movement of the cardiac chambers is minimal. This phase is ideal for cardiac imaging as it provides the clearest images of the cardiac structures.

**Why Each Wrong Option is Incorrect**
**Option A:** Early systole is incorrect because this phase is characterized by rapid contraction of the heart, resulting in significant motion.
**Option B:** Mid-systole is incorrect because this phase also involves significant cardiac motion due to the ongoing contraction of the heart.
**Option C:** Early diastole is incorrect because although it marks the beginning of the relaxation phase, the cardiac chambers still undergo some movement.

**Clinical Pearl / High-Yield Fact**
It is essential to understand the cardiac cycle and the phases of motion to optimize cardiac imaging techniques, such as cardiac MRI or CT scans, to obtain high-quality images.

**Correct Answer:** C. Late diastole