In a mammalian cell, protein synthesis is regulated at the level of initiation by various kinases. During viral infection, which one of the following kinases is involved in regulating the step of formation of elF2.GTP.Met tRNAi ternary complex in the host? (A) Heme-regulated inhibitor kinase (HRI) (B) Protein kinase RNA dependent (PKR) (C) GCN2-like kinase (D) PKR-like endoplasmic reticulum kinase (PERK)