Consider evacuation for two identical robots $($with wireless communication$)$ when the exit is on the perimeter of a unit disk $($with position unknown to the robots$)$ and the robots start at the same time and are co$-$located at the center of the disk. To search for the exit the robots start at the center, go to antipodal positions on the perimeter, and search the perimeter clockwise. For any starting configuration of the robots there is an algorithm so that the sum of the distances covered by the two robots until evacuation is accomplished is at most

Question $7$ options:

$3+2\backslash$pi

$4+2\backslash$pi

$4+\backslash$pi$/2$

$4+\backslash$pi$/3$

$4+\backslash$pi