Final answer:
The correct answer is People's Liberation Army (P.L.A.), which is the armed forces of the People's Republic of China.
Step-by-step explanation:
The correct answer is B) People's Liberation Army. In the context of the question, P.L.A. stands for People's Liberation Army, which is the armed forces of the People's Republic of China. The Shanghai base of P.L.A. Unit 61398 has been identified as a hub of cyberspying on U.S. institutions. This unit is believed to be responsible for numerous cyber-attacks and espionage activities targeting American organizations and institutions.