Questions: There are three energy-saving innovations that can benefit the economy and the environment: the solar oven, the absorption refrigerator, and the human-powered energy bicycle.

The answer is the fourth one: "There are three energy-saving innovations that can benefit the economy and the environment: the solar oven, the absorption refrigerator, and the human-powered energy bicycle."

Explanation for each option:

1. "You would have no lights, television, computer, appliances, phones, heating, or cooling."

   • This sentence sets the context by highlighting the importance of electricity in modern life but does not introduce the main topic or argument of the paragraph.

2. "While you would probably not choose to live without modern conveniences, there are several ways to cut down on power usage."

   • This sentence suggests a general idea about reducing power usage but does not specify the main points that will be discussed.

3. "Can you imagine your life without electricity?"

   • This is a rhetorical question meant to engage the reader but does not serve as the thesis statement.

4. "There are three energy-saving innovations that can benefit the economy and the environment: the solar oven, the absorption refrigerator, and the human-powered energy bicycle."

   • This sentence clearly outlines the main points that will be discussed in the text, making it the thesis statement.

Summary: The thesis statement of the introductory paragraph is: "There are three energy-saving innovations that can benefit the economy and the environment: the solar oven, the absorption refrigerator, and the human-powered energy bicycle." This sentence introduces the main topics that will be elaborated upon in the text.