Which of the following best defines transactions over the World Wide Web?

E-commerce is best defined as the buying and selling of goods and services over the Internet. It encompasses a wide range of online business activities, including online retail shopping, electronic payment processing, and the transfer of data to facilitate these transactions. E-commerce leverages the World Wide Web as its primary platform, allowing businesses and consumers to engage, conduct transactions, and communicate seamlessly from anywhere in the world.

The other choices do not specifically denote transactions over the World Wide Web. Networking relates to the interconnection of computers and other devices to share information but does not inherently involve commercial transactions. Cloud computing refers to accessing and storing data and applications over the Internet rather than on a local computer, which is more about infrastructure than the act of buying or selling. Digital marketing involves promoting products or services online but does not specifically define the transactional aspect itself. Thus, e-commerce is the most precise term to describe transactions over the World Wide Web.