[quote=Revolutionary]
Acceptable. Maybe not correct, but acceptable, since I wasn't certain about number.
[/quote]

Oh yeah, acceptable. But remember that "they" only applies to a group when you're taking the SAT. They like to throw that. For a guy, you're "supposed" to say "He or she" "He or she went to the store."[quote=whizzball1]
It's used in business all the time. If the uptight perfectionist businessmen are using it, it must be okay.
[/quote]

Acceptable socially, but not correct. It's stupid how tests don't allow for the evolution of the English language, but whatever.