Dodecane in presence of platinum gives a mixture of:

The correct option is D i.e Heptane and pentene
Pyrolysis is defined as the conversion of a compound into smaller fragments in the absence of air through the application of heat.
In the absence of air when Alkane vapours are passed through red-hot metal it breaks down into simpler hydrocarbons. This process takes place at high temperatures and high pressure without a catalyst. At low temperatures and pressure, the presence of a catalyst such as platinum or palladium is required for this reaction.

Dodecane in presence of platinum gives a mixture of Heptane and Pentene.

Reaction: $C_{12}{H}_{26}\underrightarrow{Pt}{C}_7{H}_{1}6+C_5{H}_{1}0$
Dodecane Heptane Pentene.