Final answer:
The correct answer is C) E2 reactions involve 4 atoms with hydrogen and X on the same side.
Step-by-step explanation:
The correct answer to the question is C) E2 reactions involve 4 atoms with hydrogen and X on the same side. In an E2 reaction, the transition state involves four atoms with the hydrogen and X on the same side. This is known as the syn-periplanar geometry. The elimination occurs in a concerted manner, meaning that the proton transfer and leaving group departure happen simultaneously. While E2 reactions do involve a transition state, it is important to note that this transition state exists at an intermediate energy level between the reactants and products.