Statement 1: Pictures can tell a story.
Statement 2: All storybooks have pictures.
Statement 3: Some storybooks have words.
If the above statement are facts, then which of the following must also be a fact?
I. Pictures can tell a story better than words can.
II. The stories in storybook are very simple
III. Some storybooks have both words and pictures.

All storybooks have picture and Some storybooks have words. Thus, Some storybooks have both words and pictures.
Hence, III is a fact. 
From the given statements none of 'Pictures can tell a story better than words can and The stories in storybook are very simple' can be concluded.

Story books is a subset of pictures and some story books have words.Story books is a subset of pictures and some story books have words.Story books is a subset of pictures and some story books have words.
Hence, option C is the correct answer.