The correct option regarding an expository sermon would be a: "it builds a bridge from the world of today."
Expository sermons focus on explaining and interpreting a specific biblical text, bringing its message to a contemporary audience. They aim to clearly communicate the Bible's teachings in a way that is relevant to today's listeners, making "building a bridge" an essential characteristic of expository preaching.
The other options (b, c, and d) do not accurately describe the nature of an expository sermon. In an expository sermon, the sermon idea should accurately reflect what the text says (not just what the pastor wants to say), and the relevance of the Bible is central to the sermon, contrary to what option d suggests.