When mean imputation is performed on data after the data is partitioned for honest assessment, what is the most appropriate method for handling the mean imputation?

When mean imputation is performed on data after the data is partitioned for honest assessment, what is the most appropriate method for handling the mean imputation?
A . The sample means from the validation data set are applied to the training and test data sets.
B . The sample means from the training data set are applied to the validation and test data sets.
C . The sample means from the test data set are applied to the training and validation data sets.
D . The sample means from each partition of the data are applied to their own partition.

Answer: B