We are given the sentence:
They took to / reading Times / for the better knowledge / in the facts.
The phrase 'for the better knowledge' is incorrect. The correct phrase should be 'for better knowledge', as 'better' does not require an article 'the' before it when referring to abstract knowledge. Additionally, 'in the facts' is not a correct phrase, and it should be 'from the facts' or 'in the facts' if referring to a location.
Thus, the error is in part (D), which should be 'in the facts' corrected to 'from the facts'.
Hence, the correct answer is option (4).