A signed integer has been stored in a byte using the $2$'s complement format. We wish to store the same integer in a $16$ bit word. We should
- copy the original byte to the less significant byte of the word and fill the more significant with zeros
- copy the original byte to the more significant byte of the word and fill the less significant byte with zeros
- copy the original byte to the less significant byte of the word and make each fit of the more significant byte equal to the most significant bit of the original byte
- copy the original byte to the less significant byte as well as the more significant byte of the word