Answer:
0xFF.
Step-by-step explanation:
The Register A of HSC12 is an 8-bit register.So the maximum value for 8 bit is 8 1's (11111111). So the decimal value for the maximum 8 bits is 255 but all the options given are in hexadecimal so among the given options only 0xFF has the value of 255 in decimal F=(1111)₂.So two F's make 8 bits and their decimal value is 255.