Tcp is a connection-oriented transport protocol and as such, provides:

a) reliable transport between the client and server processes
b) timing - or controlled delivery of data
c) security
d) minimum throughput guarantees

The right answer is A).

Explanation:

TCP, is the transport layer protocol  of the TCP/IP suite, and is the one that guarantees a reliable transport between the two ends of a client-server process taking care that all packets (TCP segments) reach to destination , and in the right order.

In order to get this, in simple words, it "listens" to the answers from the remote end, receiving wich is called an acknowledgement (ACK) from the another site, that is also time-related to the last segment sent, which it is included in the TCP Header.

In this way, it can check if the different segments (that also identifies the application process through the "port " concept) are arriving to destination, and in which order.