The correct option is D wood
The substances that burn in presence of air to produce heat and light are called combustible substances.
Eg:- Wood, coal, charcoal, kerosene, petrol, diesel, liquified petroleum gas (LPG), compressed natural gas (CNG), etc.
Substances like stone, glass, iron nails, etc. do not burn on being exposed to flame as they have high Ignition temperature. Such substances are called non-combustible substances.