I am confused.
I never used this extraction and I cannot test it so I hope someone else will for the definitive answer. However, I expected the asnwer to be two based on reading exactly the article that is mentioned in the explanation.
The article describes the phases of the process. Splitting on word boundaries is the first, followed by tagging. In that phase "The" and "is" are discarded; "date" is tagged a noun; "January" is tagged a proper noun, and "4" and "2015" are tagged as number.
But these four words are not all returned, that is determined in a later phase depending on the configuration of the component - nouns only, noun phrases only, or both.
The word "date" clearly qualifies as a noun. "January", a proper noun, does the same. I am not sure if "4" and "2015" are added to make this a noun phrase or not, as all the examples focus on adjectives. So the second returned term might be either the noun "January" or the noun phrase "January 4, 2015".
Perhaps I am misreading something. Perhaps numbers are also considered nouns, in which case the article is misleading. I do not have an SSIS installation at hand so I cannot test it, but I hope someone else will, and then share the results here.