By definition
Interpolation is a statistical method by which related known values are used to estimate an unknown price or potential yield of a security. Interpolation is achieved by using other established values that are located in sequence with the unknown value
An extrapolation is an act or instance of inferring an unknown from something that is known. Statistics, Mathematics. the act or process of estimating the value of a variable or function outside the tabulated or observed range
Therefore,
Of the two methods Interpolation is preferred
This is because we have a greater likelihood of obtaining a valid estimate