Answer: -1.88%

The correct answer is C (-1.88%) as explicitly stated in the provided text. This question appears to be testing understanding of simple return calculations in quantitative analysis. Simple return is typically calculated as (Current Price - Previous Price) / Previous Price. In this case, the negative return of -1.88% indicates a decrease in value at time 4 compared to the previous period.

Author: Tanishq Prabhu