Task: Class Definition Understanding (ontology: Sciences/Biology)

Which of the following definitions best describes 'activated CD8-positive, alpha-beta T cell'?

A. A CD8-positive, alpha-beta T cell that is capable of killing target cells in an antigen specific manner with the phenotype perforin-positive and granzyme B-positive.
B. A CD8-positive, alpha-beta T cell with the phenotype CD69-positive, CD62L-negative, CD127-negative, CD25-positive, and CCR7-negative.
C. A CD8-positive, alpha-beta T cell that has not experienced activation via antigen contact and has the phenotype CD45RA-positive, CCR7-positive and CD127-positive. This cell type is also described as being CD25-negative, CD62L-high and CD44-low.
D. A CD8-positive, alpha-beta T cell with the phenotype CD69-positive, CD62L-negative, CD127-negative, and CD25-positive, that secretes cytokines.

Answer: A CD8-positive, alpha-beta T cell with the phenotype CD69-positive, CD62L-negative, CD127-negative, CD25-positive, and CCR7-negative.