Is it obligatory to signal while deviating to the right or to the left from the driving lane?

1. It is not obligatory to signal while deviating from one lane to the other.
2. It is not obligatory to signal during an insignificant deviation from the lane.
3. Correct answer: It is obligatory to signal before any deviation from the driving lane, until it is completed.
4. It is not obligatory to signal if the deviation is significant and noticed by all drivers

WhyYou signal for every deviation from your lane, and the signal stays on until the maneuver is complete. A small shift counts too.