Answer:
Option (3).
Explanation:
Endospore may be defined as the type of non-reproductive produced by the some bacterial species. The endospore formation occurs in unfavorable environment like lack of nutrients and drought condition.
Dipicolinic acid is present in large amount in the endospores. These endospores are resistant to may stresses like salinity, drought and generally kills the vegetative cells of the bacteria.
Thus, correct answer is option (3).