Coke is produced
(A) When coal is strongly heated continuously for 42 to 48 hours in the absence of air in a closed vessel
(B) From the finely ground coal by moulding under pressure with or without a binding material
(C) When coal is first dried and then crushed to a fine powder by pulverizing machine
(D) By heating wood with a limited supply of air to a temperature not less than 280°C