Answer:
Technician A
Step-by-step explanation:
A refractometer is a device which tells us the concentration of a substance within a given solution. The refractometer works using the refraction principle.
To read the battery's specific gravity using the refractometer, we have to point it towards a source of light then focus till we can visibly see the scale.
The scale value on a refractometer is read at a point where the dark and the light portions meet.
So technician A is correct