E2B03

How is an interlaced scanning pattern generated in a fast-scan (NTSC) television system?

1. ABy scanning two fields simultaneously
2. BBy scanning each field from bottom-to-top
3. CBy scanning lines from left-to-right in one field and right-to-left in the next
4. DBy scanning odd-numbered lines in one field and even-numbered lines in the next

Pick an answer to check it.