The correct answer is: D. Differential pricing of internet services
Net neutrality is the principle that internet service providers should treat all data on the internet the same, and not discriminate or charge differently by user, content, website, platform, application, type of attached equipment, or method of communication.
Option A is incorrect because net neutrality does not prevent people from using the internet. In fact, it is designed to ensure that everyone has equal access to the internet.
Option B is incorrect because net neutrality does not involve subsidizing internet services. In fact, it is designed to prevent internet service providers from charging different prices for different types of internet traffic.
Option C is incorrect because net neutrality does not involve providing free internet services. In fact, it is designed to ensure that everyone has equal access to the internet, regardless of whether they can afford to pay for it.