Final answer:
Condensation of steam on the glass represents a decrease in entropy, as it involves a change from a high-entropy gas to a lower-entropy liquid.
Step-by-step explanation:
The process that represents a decrease in entropy is condensation of steam on the glass. Entropy is a measure of the disorder or randomness in a system, and when steam condenses on a glass, it transitions from a gas (which has high entropy due to the random movement of particles) to a liquid (which has lower entropy because the particles are more ordered). Thus, the entropy decreases. In contrast, sublimation, boiling, and dissolving generally increase the disorder and thus the entropy of a system.