Answer:
Option C:- Concentration
Explanation:
Coal dust explosion can cause lots of damage. To avoid
this, the amount or concentration of coal dust per unit
volume or MEC is measured with the various conditions
of coal storage such as the particle size, moisture of coal,
degree of dispersion and delayed time of ignition source
to prevent the coal dust explosion which aims to study
and design the explosion safety measures for coal dust
handing installations. The results present that moisture
content in coal has more effect on dust explosion. The
smaller size of particle, low moisture in coal and high
coal dust dispersion can increase the possibility or risk of
dust explosion.