Definition: You are given a question on machine learning. You are also given 4 answer options (associated with "A", "B", "C", "D"), out of which only one is correct. You need to answer the question by selecting the correct option. You should only answer with the choice letter, not the whole answer.
Input: You are reviewing papers for the World’s Fanciest Machine Learning Conference, and you see submissions with the following claims. Which ones would you consider accepting? 
(A)My method achieves a training error lower than all previous methods! (B)My method achieves a test error lower than all previous methods! (Footnote: When regularisation parameter λ is chosen so as to minimise test error.) (C)My method achieves a test error lower than all previous methods! (Footnote: When regularisation parameter λ is chosen so as to minimise cross-validaton error.) (D)My method achieves a cross-validation error lower than all previous methods! (Footnote: When regularisation parameter λ is chosen so as to minimise cross-validaton error.)
