An epidemic (or epiphytotic) is the development of disease:a. On a susceptible plant b. On a plant c. Within a population of plants d. On a plant leafe. None of the others

The correct option is "C".

Explanation:

to world epidemic means " the appearance of a particular disease to affect disproportionately a large number of individuals within a population.

hence, epidemic or epiphytotic is the development of a disease "within a population of plants".

The answer is B

Explanation:

An epidemic or epiphytotic is the development of plant disease that occur sporadically over and over and affects large numbers of susceptible plants.