What does it mean that Gatsby knew when to stop "? Help ASAP

Identify the participle or infinitive phrase in the sentence below

If you had read the label carefully, you wouldn’t have bought the expired product.what does it means? a. you didn’t buy the expired product because you read the level carefully.b. you didn’t read the label carefully so you bought the expired product.

Which quotation from the passage best supports the themethat humans have a natural desire to learn about theworld? "they were men. i remember the dead man's face.""at least, we make a beginning."and the magic tools are broken—but we can look atthem and wonder."but they were men who built the city, not gods ordemons.