Which of the following can be one of the steps in stacking?
1. Divide the training data into k folds
2. Train k models on each k-1 folds and get the out of fold predictions for remaining one fold
3. Divide the test data set in "k" folds and get individual fold predictions by different algorithms

A. 1 and 2

B. 2 and 3

C. 1 and 3

D. all of above

Answer: Option A