What is the function of the hydroxyl group in organic compounds?

I - To make the compound polar.
II - To make the compound nonpolar.
III - To give the compound acidic properties.
IV - To give the compound basic properties.
a) Only I and III are correct.
b) Only II and IV are correct.
c) Only I and IV are correct.
d) Only II and III are correct.
e) I, II, III and IV are correct.