Tetrahedral geometry.

Valence shell electron pair repulsion theory plays an important role in organic chemistry, within which stereochemical considerations are so important. For the MCAT, you must understand which forms have a linear, trigonal planar, or tetrahedral geometry (including non-bonded electron pairs) among alkanes, alkenes, alkynes, the hydroxyl group, carbonyl, carboxyl, and amine. Questions that directly depend on VSEPR reasoning are common on the MCAT, let alone questions that indirectly depend on this topic.