Knows little. 2 and 3 are both presuming too much, as it's the writer's duty to get them interested and informed. 4 basically doesn't matter, and furthermore may not even apply in many forms of writing. 1 is the best answer, as writing for general audiences is intended to inform and expand the horizons of the reader.
Answer:
A measurement of the sensitivity of the value of an option to changes in the implied volatility of the price of the underlying product.
Explanation: