Right Answer is:
We use the preposition “for” to talk about an amount of time or space. The amount of time could be seconds, minutes, hours, days, months or even years. The amount of time does not need to be exact. You could use for when you are talking about vague periods of time. We use “since” to refer to a point of time. “Since” refer to a point after a specific time or event in the past. Or it can refer to a particular point beginning sometime in the past and continuing until the present time.
Hence, option B is the correct answer.