Which option is a practical storage point for ligase?

Correct answer: Keep it under cold conditions

The governing concept is preservation of protein-enzyme activity. Ligase is a protein, and excessive heat can disrupt its three-dimensional structure, denature the active site, and reduce or destroy catalytic activity. Keeping a laboratory enzyme under the recommended cold conditions, commonly on ice during handling and in a suitable freezer for longer storage, slows degradation and helps retain activity. Thus option A is the best practical answer. Boiling is deliberately destructive to most enzymes, direct sunlight can supply heat and damaging radiation, and mixing the preparation with soil offers no controlled preservation. Exact temperature and buffer depend on the product protocol.