The correct options are
B Hydrocarbons are carcinogenic.
C Hydrocarbons harm plants by causing ageing, shading of leaves, flowers and twigs.
The following are true regarding hydrocarbons
Hydrocarbons are produced due to incomplete combustion of fuel used in automobiles.
Hydrocarbons are carcinogenic.
Hydrocarbons harm plants by causing ageing, shading of leaves, flowers and twigs.