Final answer:
Option A could be a good replacement for sentence 4 to introduce the topic of the passage as it gives a general overview of bike share programs, but the effectiveness of any option depends on the full context of the passage.
Step-by-step explanation:
Without viewing the entire passage it's difficult to ascertain which sentence best introduces the topic. Ideally, the sentence should provide a broad and clear overview of what the passage is about, and set the stage for the details that follow. However, generalizing from the options given:
- a. bike share programs have become an accessible and environmentally friendly solution for many urban travelers.
- b. bike share programs are successful because both residents and tourists can use the bicycles to travel within a city.
- c. bike share programs offer an alternative form of transportation in urban areas that is faster than using a car or taxi.
- d. bike share programs have created an affordable mode of transportation for people in large cities throughout the world.
Option A might be a strong choice as it provides an overview of what bike share programs are and their benefits - accessible, environmentally friendly, and suited to urban travelers. Of course, how well any specific option works depends greatly on the content of the entire passage.
Learn more about Introducing a passage