Final answer:
The most frequent site of extra-pulmonary manifestation in sarcoidosis is the B. skin. This systemic inflammatory disease can affect multiple organs, with skin lesions being particularly common.
Step-by-step explanation:
The most frequent site of extra-pulmonary manifestation in sarcoidosis is the skin. Sarcoidosis is a systemic inflammatory disease that primarily affects the lungs, but it can also involve multiple other organs. While liver, eye, and heart manifestations can occur, skin involvement is often prominent and includes a variety of lesions such as erythema nodosum, lupus pernio, and others. It's important for patients to be monitored for these conditions as part of their overall disease management.