What term is used to describe plants that consist of a single cell?

Explanation

Single-celled plants are classified as Protophyta. Option A, 'B. Protest,' is incorrect and likely a typographical error. Protozoa (Option C) are single-celled organisms but are considered animal-like, not plants. Prokaryotes (Option D) are organisms without a defined nucleus, such as bacteria, and are not classified as plants.