**Core Concept:**
The 'c' wave of jugular venous pulse (JVP) is a pulsatile rise in the jugular venous pressure (JVP) occurring in the late systole and early diastole. It is a clinical sign indicating increased central venous pressure (CVP), often caused by right heart failure or venous congestion. The 'c' wave is a result of the right atrial contraction pushing the blood into the superior vena cava (SVC) and right atrium, which then empties into the right ventricle.

**Why the Correct Answer is Right:**
The correct answer (Option C) refers to the physiological explanation of the 'c' wave. The 'c' wave occurs due to the right atrial contraction during late systole, which pushes blood into the SVC and right atrium. The right atrium then empties into the right ventricle, causing the 'c' wave to appear in the JVP.

**Why Each Wrong Option is Incorrect:**
Option A is incorrect as it does not explain the 'c' wave; instead, it describes the 'a' wave, which represents the rise in JVP due to the fall of the diaphragm during inhalation. Option B is incorrect because it does not mention the key component of right atrial contraction and its contribution to the 'c' wave. Option D is incorrect because it only addresses the 'a' wave without explaining the 'c' wave and its relationship to right atrial contraction and CVP increase.

**Why Option C is Correct:**
Option C explains the 'c' wave appropriately, referring to the right atrial contraction during late systole and its effect on the JVP. This option correctly describes the relationship between right atrial contraction and the increased central venous pressure (CVP) seen in the 'c' wave.

**Clinical Pearl:**
The 'c' wave is a clinical sign indicating increased central venous pressure, often seen in conditions like right heart failure or venous congestion. Auscultating the JVP in conjunction with clinical examination and history can help clinicians diagnose and manage such conditions appropriately.