Which is the best definition for blocks as it is used in this sentence?

the peachtree road race in atlanta, ga is the world’s largest 10k, boasting 55,000 runners who line up for blocks at 7: 30am to run down atlanta’s most famous street.

definitions:
1. a solid piece of a hard substance, such as wood, having one or more flat sides.
2. a stand from which articles are displayed and sold at an auction
3. a mold or form on which an item is shaped or displayed.
4. a measurement referring to the distance between intersecting city streets.