The correct option is B Golgi body
The densely stained reticular structures were found by Camillo Golgi, near the nucleus. These structures were later called Golgi bodies, which consist of many flat disc shaped sacs called cisternae stacked parallel to each other. The Golgi cisternae are concentrically arranged near the nucleus with distinct convex cis (forming) face and concave trans (maturing) face. So, the correct option is B.