This one would have to be A! All of the others are wrong!
3. would be/knew how
The first blank must be future tense because the word after it ends in -ing
The second blank must be ____ how, and it must be past tense, so knew how. She knows <em><u /></em><em>why </em>the business would be started, to provide a great public service, but not <em>how</em>.
I'm not sure but here's the definition of Parallel Structure. ( Using the same pattern of words to show that two or more ideas have the same level of importance). You can go with either the first or second sentence that's my opinion but I'm really not 100% sure. Sorry I couldn't been more helpful. I tried
Is ok go and have a great life
