Consider an 8-pin general purpose input/output port memory mapped to address " adr_gpio_a ". What does the following code do?

ldr r0, adr_gpio_a ldr r1, =0xfb str r1, [r0, #4] ldr r2, [r0]

• A.

  Sets pin 2 as input, the remaining pins (0,1, 3..7) as output, then reads from pin 2.

• B.

  Sets pin 2 as output, the remaining pins (0,1, 3..7) as input, then reads from every pin except pin 2.

• C.

  Writes the value 0xfb to the memory cell adjacent to the i/o port, then reads input from all of the pins in the port.

• D.

  Reads the input from the i/o port and applies a bit mask of 0xfb.