What is the inverse of:

If a = b and b = c, then a = c

1) a = b and b = c if, and only if, a = c
2) If a ≠ c then a ≠ b or b ≠ c
3) If a ≠ b or b ≠ c, then a ≠ c
4) If a = c, then a = b and b = c