Which of the following conditions relates specifically to chain infections?

Cellulitis is an infection that often arises when bacteria enter the skin through a cut or break, leading to inflammation and infection of the tissues beneath the skin. This condition is particularly related to chain infections because it can occur when bacteria multiply and spread through the lymphatic or circulatory pathways, resulting in a widespread infection. The nature of cellulitis as an infectious process makes it distinctly linked to the concept of chain infections, where pathogens are transmitted and proliferate within a host.

In contrast, hypertension and diabetes are chronic non-infectious conditions that do not involve infectious agents or chain infection mechanisms. Myocardial infarction, commonly known as a heart attack, is an event caused by reduced blood flow to the heart muscle, typically due to obstruction from plaque buildup, rather than due to an infectious agent. Hence, cellulitis stands out as the condition most directly associated with chain infections due to its infectious nature and the way it can spread through infection pathways.