Correct Answer: B
Explanation:
The first clause of the sentence contrasts a time when surfing was sociable with the present, so the last half of the sentence must describe an antisocial action. The word but tips off the contrast. Choices B an offense and D a discourtesy are the only two that contrast with sociable. An offense is the better choice, because a discourtesy is not strong enough to fit well with heinous (shockingly evil).
| Heinous: | outrageously evil or wicked; abominable |
| Adage: | an old saying that has been popularly accepted as a truth |