The author is an aggressive, brilliant and literate astronomer. This vastly entertaining book has a simple manner with complex ideas, without being patronizing, and is often very funny.
In 274 pages Sagan deals with everything from the formation of the Earth to the puzzling possibilities of contact with extra-terrestrial life. This is the moment in history when man's stepping into the universe has suddenly become conceivable. To Sagan this is more exciting and important than was the exploration of the New World in the sixteenth century. So expenditure on the space programme, pruned of recent excesses, ought to continue--it is, according to Sagan, no larger a part of America's gross national income than was the relative cost to England in the sixteenth century of exploration in sailing ships.
The book is not for scientific illiterates, nor is Sagan a pedestrian scientist. Although he makes short work of the unidentified foreign objects (UFO) spotters, he is unafraid to take us on a speculative journey to a black hole which, for all he knows, might be the quick route to somewhere else, not necessarily our universe.
Sagan exhibits a passionate interest in life in the cosmos in which there are .almost certainly civilizations much more advanced than our own. We are the result of a number of relatively recent cosmic accidents, but for all that, Sagan is no less excited about our future,
From the passage we understand that Carl Sagan writes ______.

A. forcefully and complexly
B. elaborately and literally
C. simply and humorously
D. snobbishly and cleverly