1. Your computer system has a 20-bit address bus and a 64-bit data bus. Which of the following statements is/are true?

a. Given that a word contains 4 bytes, the CPU can send 8 words to the memory simultaneously;

b. The system can accommodate a memory space of 4GB;

c. The keyboard can use 0x7FFFFFFF as the address for its register;

d. It is allowed to write a byte into RAM or ROM;

e. None of the above.