An herbarium is a repository of preserved and labeled plant specimens that serve easy access and archival storage. It has specimens in form of herbarium sheets. The collected specimens are pressed and dried and then pasted on a sheet of heavy paper together with a data label. The useful information including the plant's Latin name, the origin of the collection, the date of collection, and the name of the collector is mentioned on the label. Herbarium sheets are all of the standard size, i.e., 42 cm x 29 cm.
Thus, the correct answer is option C.