This question has a sentence with two blanks followed by four pairs of words as choices. From the choices, select the pair of words that can best complete the given sentence: 

We are truly ______ to the many hands and hearts that made this book ______.

The sentence likely refers to an author, a group of authors, or publishers, who appreciate the many hands and hearts (essentially, the many people) involved in the making of the book. Usually, in such contexts, we refer to the people as having made the writing of the book 'possible' and are thankful/ grateful to them. The best pair of words that captures this is in option C, which is the correct answer.