Final answer:
Sugar can help stabilize egg foam, but this is situationally true because the timing and amount of sugar are crucial for effective stabilization. Sucrose is stable and does not break down without activation energy.
Step-by-step explanation:
The question addresses whether sugar always stabilizes egg foam. The answer is situationally true (c). While sugar can indeed help stabilize egg whites by providing structure to the foam, it must be added at the right time and in the right amount in order to be effective. If too much sugar is added too early, it can weigh down the egg whites and prevent them from reaching full volume. Regarding sucrose, it is a stable compound that requires activation energy to break down, thus you can store it in a sugar bowl without it spontaneously breaking down into simpler sugars.