Read the facts like a checklist rather than a story. The Penal Code first asks whether an act fits the definition of a crime, and then asks whether a general exception rescues it. X's shot mortally wounded Z, so on the surface X caused death. But the Code carves out acts done in good faith for the benefit of a person when consent cannot be had. Test X against that carve-out phrase by phrase: good faith, benefit of the other, no intent to cause the harm, and no chance to ask for consent.
So option (C) is the answer. Notice the deliberate wording in the problem, "knowing that the shot might kill Z, but with no intention to kill Z". The Code separates knowledge of a risk from intention to bring about a result, and it is that separation, plus the good faith, that saves X.
Let's summarize:
X fired in good faith to save Z from a tiger, so he committed no offence, and option (C) is correct.