Why use a vpn for client-to-server connections over the internet?

VPN's are when your IP address is hosted securely over a network to provide connectivity. It does this by encrypting all data that is sent across the network. Usually, in fact, almost always VPN's are used for C2S (client to server) connections to ensure data gets transmitted over a network confidentially. The internet is a C2S network where the server is the internet and the client is your workstation. The biggest issue with transmitting data and connections across networks is that they can be interfered by network traffic and can be interfered with by malicious users. VPN's ensure that this cannot happen. 

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The answer is d) all of the above