The correct answer is D. A photographer.
Step-by-step explanation
Mathew Brady was a renowned portrait photographer who was born in a humble Irish family in Warren County, near Lake George. As a teenager, he moved to New York City at the age of 16, where he worked as an employee in a department store, subsequently became independent and opened his own jewelery case store, in parallel venturing into painting by painting miniatures. Mathew Brady was noted for the mastery he had for the portrait, his talent led him to win the highest medal at the first world fair of the Crystal Palace in 1851. His popularity extended so much that he had to delegate his studio portraits to his assistants , especially, Alexander Gardner who helped him from 1856 to 1863. So, the correct answer is D. A photographer