In the Parable of the Sower (Matthew 13:1-23), what does the seed that falls on rocky ground represent?

A Those who hear the word but worldly anxieties choke it. B Those who hear the word and immediately receive it with joy, but have no root. C Those who do not understand the word. D Those who hear the word and produce a crop, yielding a hundred, sixty or thirty times what was sown.