Step 1: Endospores are tough, dormant structures a small group of bacteria form to survive heat, drying and chemical stress.
Step 2: This ability is mainly restricted to Gram positive genera such as Bacillus and Clostridium. Streptococcus, Escherichia and Pseudomonas do not form true endospores.
Step 3: Since Clostridium (for example Clostridium tetani and Clostridium botulinum) is well known for endospore formation, option (B) is correct.