To have a drink in a bar alone?

[Acunningruse]

Tonight I finish work at 6pm. DS finishes his class in the next town at 7:30pm. To go home first I would be going out of my way by about 15 minutes.

Would you, whilst waiting for DS:
A) work late
B) go home then go out again
C) go to supermarket - nothing immediately essential needed but could always get some bits
D)go for a walk (though town not most scenic)
E) go to a bar and have a small glass wine
(as driving)
F) something else?

A police friend of mine told me never to take the risk of even one drink because there are so many factors involved eg weight, are you also eating, gender etc. It's not an exact science.