The correct answer is: C. Standalone companies are specifically barred from covering rural masses.
Option A is correct because hospital chains are allowed by IRDA to enter health insurance business. This is a recent phenomenon as it was not allowed earlier.
Option B is correct because standalone companies have tapped into the tremendous growth of health insurance business. This is a recent phenomenon as standalone companies were not very successful in the past.
Option C is incorrect because standalone companies are not specifically barred from covering rural masses. In fact, many standalone companies have been successful in covering rural masses.
Option D is incorrect because all of the options are not recent phenomena.