The correct answer is A. decimal.
Hexadecimal is a base-16 number system, which means that it uses 16 different digits to represent numbers. These digits are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F.
Decimal is a base-10 number system, which means that it uses 10 different digits to represent numbers. These digits are 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
Binary is a base-2 number system, which means that it uses 2 different digits to represent numbers. These digits are 0 and 1.
ASCE is a standard for the representation of information in the United States. It is not a number system.
BCD is a binary-coded decimal number system. It is a way of representing decimal numbers using binary digits.
Hexadecimal is a convenient number system to use for computers because it is easy to convert from hexadecimal to decimal and vice versa. To convert from hexadecimal to decimal, you multiply each digit in the hexadecimal number by its place value, starting with the rightmost digit and working your way to the left. The place values are 16^0, 16^1, 16^2, and so on. For example, to convert the hexadecimal number 123 to decimal, you would multiply 1 by 16^2, 2 by 16^1, and 3 by 16^0. This gives you 256 + 32 + 3 = 291.
To convert from decimal to hexadecimal, you divide the decimal number by 16 and keep the remainder. You then divide the quotient by 16 and keep the remainder, and so on. The remainders will be the digits of the hexadecimal number, starting with the rightmost digit. For example, to convert the decimal number 291 to hexadecimal, you would divide 291 by 16. This gives you 18 with a remainder of 15. You then divide 18 by 16. This gives you 1 with a remainder of 2. You then divide 1 by 16. This gives you 0 with a remainder of 1. The digits of the hexadecimal number are 1, 5, and 2, which is the number 123.
Therefore, the main advantage of hexadecimal numbers is that they are easy to convert from hexadecimal to decimal and vice versa.