A portion of the following sentence is highlighted. Choose the option that best replaces the highlighted portion. If no improvement is required, choose Option D: "No improvement required."

Regular exercise will have the effect of boosting your energy levels and reduce your daily stress.

The correct option to replace the highlighted portion is "boost your energy levels and reducing".

Detailed Explanation:
1. Eliminating Wordiness and Improving Directness: The original phrase "have the effect of boosting" is unnecessarily wordy and indirect. Replacing it with the single active verb "boost" creates a concise, clear, and more impactful sentence.
2. Analyzing the Options:
• No improvement required: Retains the wordy and indirect phrase "have the effect of boosting".
• affect the boosting of your energy levels and reduce: Uses awkward and unnatural phrasing ("affect the boosting").
• have the affect of boosting your energy levels and reducing: Misuses the verb "affect" in place of the noun "effect".
• boost your energy levels and reducing: Correctly streamlines the sentence by replacing the wordy construction with the direct action verb "boost".

Therefore, the best replacement for the highlighted portion is boost your energy levels and reducing.