Producer gas is obtained by

A)
carbonisation of bituminous coal
B)
passing steam over incandescent coke
C)
passing air and a large amount of steam over waste coal at about 650°C
D)
partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast

Correct Answer : Option (D) :   partial combustion of coal, coke, anthracite coal or charcoal in a mixed air steam blast