Peter designed a quad buffer port expansion sub$-$system and begins programming his Arduino Mega$2560$ to interface with the system. Peter reads the datasheet documentation and learns that the ATmega microcontrollers uses the PINx port for input. Which lines of code need to be written to read data from the system into the ATmega$2560\text{'}$s port?

A$.$

DDRD $=0$xff;

PORTD $=0$;

B$.$

DDRD $=0$x$0$f;

PORTD $=0$xf$0$;

C$.$

DDRD $=0$;

PORTD $=0$xff;

D$.$

DDRD $=0$;

PORTD $=0$;