Overtaken vehicle, must slow down + go close to the right.
Answer 1 is wrong because of speeding up, Answer 3 is wrong because go to the side left.
Increase speed and signal to the vehicle behind to overtake, do not obstruct the vehicle behind to pass.
The driver of the vehicle in front must slow down, stay close to the right of the roadway until the vehicle behind has passed, and must not obstruct the vehicle behind to pass.
For the vehicle to avoid to the left and signal to the vehicle behind to pass; if there is an obstacle ahead or there is a lack of safety conditions, it must signal to the following vehicle; not to interfere with the vehicle please pass.