I'm actually not sure about the answer here. I am certain that A and C are correct answers, as reading is definitely important for word building, as well as using a dictionary is. But B and D are dubious. Because, when you don't know how a certain word is pronounced, you will usually look it up in the dictionary, you will see the way it is pronounced, but also what it means, so that way you can build your vocabulary. And again, if you memorize lists of words, it is a way of building your vocabulary. So the incorrect sentence is either B or D.
