Parameters of the "response":
1. Must be visibly impressive for both internal and external observers, lots of fireworks. Hanya assassination was the most humiliating thing the regime experienced since Soleymani. The "revenge" needs to be spectacular in appearance to match it.
2. Must do some actual series damage to Israel. To restore - in their minds - the deterrence they lost lately.
3. Must not serious enough to warrant catastrophic Israel response with International legitimacy. Meaning no large scale loss of life, especially amongst civilians.
Taking it all together, several options:
1. High practucal value target - airforce base, gas rig etc.
2. High symbolic value target - the Kirya or Knesset building (Pentagon, Parliament).
3. Hitting residence of Bibi or one of the ministers.
4. Some fireworks in Israel without actual damage + terrorist attack against Jewish/Israeli targets abroad.
IMHO etc.