In the following passage, some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.

This was enough ___________ the book store-owner-turned librarian Husain to asses its valuable contents. "The preface of the book read: 'painters __________ technical knowledge to paint, but lack to understand nature, ______________ they fail to create a masterpiece," points out Husain, adding, "All I ______________ in my life is about books and from books. The grand library ___________ the palace is a cache of knowledge."

to understand nature, ______________ they fail to create a masterpiece

• if

• that

• hence

• this