Which option below correctly describes the domain of (see image) and explains why the range of b is not all real numbers? a. the domain is all real numbers less than or equal to 81. the range is not all real numbers because the square root of a negative number is not a real number. b. the domain is all real numbers less than or equal to 81. the range is not all real numbers because the square root symbol applied to a non-negative number is non-negative. c. the domain is all real numbers greater than or equal to 81. the range is not all real numbers because the square root of a negative number is not a real number. d. the domain is all real numbers greater than or equal to 81. the range is not all real numbers because the square root symbol applied to a non-negative number is non-negative.