This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Transpo Processes, Subject name: Physiology
Which statement is true for both pinocytosis and phagocytosis? 
Select and explain. 
A. Involves the recruitment of actin filaments, B. Occurs spontaneously and nonselectively, C. Endocytotic vesicles fuse with ribosomes that release hydrolases into the vesicles, D. Is only observed in macrophages and neutrophils
A: Involves the recruitment of actin filaments
Answer: A: Involves the recruitment of actin filaments 
Explanation: Both pinocytosis and phagocytosis involve movement of the plasma membrane. Pinocytosis is cell drinking, whereas phagocytosis is cell eating. Both events require the recruitment of actin and other cytoskeleton elements. Phagocytosis is not spontaneous and is selective, being triggered by specific receptor-ligand interactions and Endocytotic vesicles fuse with ribosomes that release hydrolases into the vesicles