Final answer:
The pressure in atm of the normal boiling point of C6H6 (benzene) is 1 atm.
Step-by-step explanation:
The normal boiling point of a substance is the temperature at which its vapor pressure is equal to the standard atmospheric pressure of 1 atm. In this case, we are looking for the normal boiling point of C6H6 (benzene). The normal boiling point of benzene is 80.1°C. Since the boiling point is defined at 1 atm, the pressure at the normal boiling point of benzene is equal to 1 atm. Therefore, the correct answer is a) 1 atm.