Final answer:
The normal room temperature in Celsius is 25°C.
Step-by-step explanation:
The normal room temperature of 77 degrees Fahrenheit can be converted to Celsius by using the conversion formula :
C = (F - 32) x 5/9
So, substituting the given value of F = 77 degrees;
C = (77 - 32) x 5/9 = 45 x 5/9 = 25°C
Therefore, the normal room temperature in Celsius is 25°C (option a).