Answer:
As it is not possible to sketch the expanded structure of given alkane, hence, option-A seems to be correct if completely drawn. I have drawn the expanded structure below.
Little Explanation to answer:
As we know hydrocarbons contain a chain of carbon atoms. This chain can be short (like ethane, propane e.t.c) or it can be long (like octane, nonane, decane or more). Hence, when alkanes with long chain are drawn it is not possible to draw the entire structure showing each and every bond (expanded structure). Therefore, to save time and paper we often draw the condense structures. Below, the alkane containing three carbon atoms is drawn in expanded and condensed form.
