What is 'TCP Slow Start'?

1. A The algorithm where a TCP connection begins by sending data at the maximum theoretical link speed and then aggressively throttles back once the first packet collision is detected.
2. B A specialized congestion control mechanism where a new connection starts with a small Congestion Window (cwnd) and doubles it every round-trip until packet loss or the 'ssthresh' is reached.
3. C The mandatory delay period imposed by the three-way handshake that prevents the client from transmitting any application-layer payload until the server has formally acknowledged the request.
4. D A client-side bandwidth throttling routine that is automatically triggered whenever the operating system detects that a background download is consuming more than 50% of the available network capacity.