In 1, though the sentence "I have good knowledge of German" is correct as a response to a question, when used by itself, the appropriate phrasing is "I have good knowledge of the German language". In 3, "whole" should be replaced with "the whole of " when used before a proper noun (Delhi). In 5, similar to 1, the correct usage is "He knows how to swim". So the incorrect options are 135; hence the answer is C.