Final answer:
The lifetime of a light bulb described as exponential with a mean of 200 days is modeled by the exponential distribution which is option (c).
Step-by-step explanation:
The situation described where the lifetime of a light bulb is exponential with a mean of 200 days is best modeled by an exponential distribution. The exponential distribution is used to model the time between continuous events or the lifetime of objects under the assumption that the events occur independently with a constant average rate.
Therefore the mathematical distribution that models this scenario is (c) Exponential distribution.