Final answer:
The Sun is expected to continue shining for approximately 5 billion more years before it exhausts its nuclear fuel and enters the final stages of its stellar life cycle.
Step-by-step explanation:
The lifespan of the Sun is a topic of interest in astrophysics, a branch of physics that deals with the properties and life cycles of stars. Based on astrophysical understanding, the Sun is about 4.5 billion years old and has been shining ever since. It is expected to continue to shine for about another 5 billion years before exhausting its nuclear fuel and going through the end stages of its life cycle, which includes expanding into a red giant and then shedding its outer layers to leave behind a compact white dwarf. Hence, the correct answer to the question of how much longer we have to wait until the Sun dies is 'c) about 5 billion years'.