Now you know what speed of flight of large birds reaches.

Solution:

This question relates to general knowledge about birds, and the answer is not derivable from the provided text. However, based on typical knowledge about bird speeds:

1. 70 km/h
2. 30 km/h
3. 90 km/h
4. 80 km/h

Without additional context or information from a specific text that this question refers to, it's impossible to definitively select the correct option. If this is a multiple-choice question from a test, the intended correct answer would depend on the source material.