ANS:A - aromatic

Aniline point of diesel is a measure of its aromatic content. Here's why:

• Aniline Point: Aniline point is the temperature at which equal volumes of aniline (a colorless oily liquid derived from benzene) and the fuel mix to form a single phase. This property is used to characterize the solvency or miscibility of the fuel with certain aromatic compounds.
• Aromatic Content: Diesel fuels with higher aromatic content tend to have lower aniline points because aromatic compounds have a greater affinity for aniline. Therefore, the aniline point of diesel is used as an indirect measure of its aromatic content.
• Significance: Aromatic hydrocarbons in diesel can affect its combustion properties, emissions profile, and solvency characteristics. Regulatory bodies often set limits on the aromatic content of diesel to control emissions of pollutants and to ensure compliance with environmental standards.