Briefly define the following TCP flag settings: URG (Urgent), ACK (Acknowledgment), and PSH(Push).

What will be an ideal response?

URG (Urgent): Indicates Urgent Pointer field should be examined. If this flag is set, the Urgent Pointer field tells the receiver where it should start reading bytes contained in the data portion of the packet.
ACK (Acknowledgment): The Acknowledgment Number field is relevant. The acknowledgment number indicates the next expected sequence number from the other TCP peer.
PSH (Push): Data travels through outbound buffers (on the sending host) and inbound buffers (on the receiving host) immediately. This is used for time-critical or single-stroke applications. Upon receipt of a packet with the Push flag set, the receiver must not buffer the data - it must pass directly up to the Application layer protocol. That explains why this treatment is normally reserved for the final TCP segment in a sequence of segments: this forces the now complete collection up to the application for immediate servicing.