A 35-year-old man presented with newly diagnosed type 2 diabetes mellitus. He had no medical history of note.
When should he inform the UK Driver and Vehicle Licensing Agency (DVLA) of his medical condition?
A . if he becomes unable to read a car number plate with one eye at 20.5 m
B . if he requires laser treatment to one eye
C . if he starts taking an oral hypoglycaemic agent
D . if he starts using basal night-time insulin
E . immediately
Answer: D