Which of the following organisms will display lipase activity on egg yolk agar?

Lipase activity on egg yolk agar is indicative of an organism's ability to hydrolyze lipids, resulting in the breakdown of fats and the production of free fatty acids. Egg yolk agar contains lecithin, which is a phospholipid, and the presence of lipase leads to a clear zone around the growth of the organism, signaling fat hydrolysis.

All three organisms listed—Clostridium botulinum, Clostridium sporogenes, and Clostridium novyi—are known to produce lipase. This characteristic is significant in various biochemical reactions and pathogenicity mechanisms.

Clostridium botulinum, for instance, is well-known for the production of botulin toxin, but it also has the ability to metabolize lipids, which aids in its survival and pathogenic capabilities in certain environments. Clostridium sporogenes and Clostridium novyi also exhibit similar traits, contributing to their ability to thrive in anaerobic conditions and play roles in the breakdown and decomposition processes.

Thus, all these organisms are capable of displaying lipase activity on egg yolk agar, culminating in the conclusion that the correct answer encompasses all listed options.