Assertion (A): Phenyl is used as a household germicide. Reason (R): Phenyl is a phenol derivative and phenol are an effective germicide.

1. Assertion (A) states that Phenyl is used as a household germicide. This is true. Phenyl solutions are commonly used as disinfectants and germicides in households. 2. Reason (R) states that Phenyl is a phenol derivative and phenol is an effective germicide. This is also true. Commercial phenyl is often a formulation containing phenolic compounds (derivatives of phenol), and phenol itself is known for its disinfectant properties. 3. Furthermore, the reason (R) correctly explains the assertion (A). The germicidal property of phenyl stems from its nature as a phenol derivative, leveraging the effectiveness of phenol compounds against germs. 4. Therefore, both A and R are true, and R is the correct explanation of A. Option (A) is the correct answer.