Answer: Tetrahedral geometry
Explanation: The structure of the acetic acid is shown in the image below.
The left carbon atom is the one which is attached to three hydrogen atoms through single bonds and to one carbon atom through single bond as well.
Thus the orbitals which are used in the process of the formation of the chemical bond between these 4 are sp3 orbitals. And these orbitals results in the formation of the tetrahedral geometry.
The right carbon atom that is attached to a carbon atom and an oxygen atom through single bonds and a second oxygen atom through a double bond has trigonal planar geometry which involves the sp2 orbitals for the formation of the bond.