What is the proper phraseology for a rendezvous if Sidewinder 204 is TOB and bolters with the tanker at Angels 4?

The correct choice involves proper phraseology for a rendezvous with a tanker, which includes maintaining awareness of altitude and communications protocols. In this scenario, "SIGNAL TANK" indicates the intention to communicate regarding the tanker, while the specific altitude of "3.5" indicates that the aircraft is at a safe and appropriate level below its previous altitude of "4" when it bolters.

The phrase "PASSING ANGELS 2.5" serves to inform the tanker that the aircraft is descending through 2.5 thousand feet, which is critical for situational awareness for both the tanker and the aircraft. The mention of "CHECK IN BUTTON 2" signifies which frequency or channel the aircraft will be using for further communication, ensuring clear and effective coordination. This complete communication ensures that all parties are on the same page regarding altitude and operational intent.

The other options do not provide all necessary details or do not follow the expected protocols for such a situation, which is why they do not serve as the proper phraseology for the rendezvous here.