A coal with high __________ content will ignite most easily.

ANS:C - volatile matter

A coal with high volatile matter content will ignite most easily. Volatile matter refers to the proportion of coal that is released as gases and vapors when coal is heated in the absence of air. It includes substances such as hydrocarbons, hydrogen, oxygen, and nitrogen compounds, as well as water vapor. Coal with a high volatile matter content tends to ignite more easily because the volatile matter releases combustible gases when heated, which can ignite and sustain combustion. Therefore, coals with higher volatile matter content are often preferred for applications where easy ignition and rapid combustion are desired, such as in industrial boilers and furnaces.