The diet of Heliothis subflexa caterpillars consists entirely of fruit from plants of the genus Physalis. These fruit do not contain linolenic acid, which is necessary to the growth and maturation of many insects other than H. subflexa. Linolenic acid in an insect' s diet is also necessary for the production of a chemical called volicitin. While most caterpillar species have volicitin in their saliva, H. subflexa does not. Which one of the following can be properly inferred from the statements above? ['No caterpillars other than H. subflexa eat fruit from plants of the genus Physalis.', 'Most species of caterpillar have sources of linolenic acid in their diets.', 'H. subflexa caterpillars synthesize linolenic acid within their bodies.', 'Any caterpillar that has linolenic acid in its diet has volicitin in its saliva.']