The correct answer is the Subject line
The subject line is usually just a very short sentence that presents the problem briefly and straight to the point.
Answer: Flashing arrow signs
Explanation:Flashing arrow signs are the symbols or signs that are used in the form of warning that is provided to the drivers on the road to indicate about the warning in advance regarding the construction work or any particular work zone is present on that road .
These warning helps the drivers to become attentive while moving on the road so that they meet any accident due to that .Also these signs are help to the construction worker because they don't face much problem due to the advance sign.
Some protocols have multiple algorithms to choose from for e.g., cryptographic purposes. During connection set up, client and server negotiate which one they'll use.
One example is the set up of a TLS connection. During the handshake, the client shares a list of its supported ciphers (the 'ciphersuites'). The server responds by indicating the best one that both sides support.