Which is the best way to combine sentences (5) and (6)?

Direction:
The following passage is an early draft of an essay. Some parts of the passage need to be rewritten.
Read the passage and select the best answers for the questions that follow. Some questions are about particular sentences or parts of sentences and ask you to improve sentence structure or word choice. Other questions ask to consider organization and development. In choosing answers, follow the requirements of standard written English.

(1) Books of travel are of all kinds, from the dry records of laborious statisticians to the trivial diaries of globe-trotters.             (2) Explorers, seamen, archaeologists, naturalists, dreamers, what type of man or woman has not written a book of travel? (3) People read their books and they appreciate a few of them and then they forget, ninety nine out of hundred. (4) Yet there are others. (5) The great books of travel are rare as great books in any other class are rare. (6) Similarly, the people of genius, personality and character are rare. (7) To write a book of travel appeals irresistibly to large numbers of persons who have no creative power, whose books are the mere reflection of a shallow curiosity and of a foolish egotism. (8) These deplorable works, though they spread a sort of suburban light upon the beautiful and wild places of earth, throw only into greater relief the achievement of the true travelers who by reason of their fortitude, their imagination, their insight and their ability to evoke the atmosphere and color of the world, have produced books that rank as literature and last for centuries. (9) Alas! There aren’t many.