16. Which of the following sets of Dewey Decimal call numbers is in the correct order?

A. 813.54 C78A, 813.54 C782A, 813.54 C780B, 813.54 C781D
B. 813.54 C782A, 813.54 C78A, 813.54 C780B, 813.54 C781D
C. 813.54 C781D, 813.54 C78A, 813.54 C782A, 813.54 C780B
D. 813.54 C78A, 813.54 C780B, 813.54 C781D, 813.54 C782A

To determine which set of Dewey Decimal call numbers is in the correct order, we need to understand how the Dewey Decimal System works.

The Dewey Decimal System is a classification system used in libraries to organize books by subject. It divides all knowledge into ten main classes and assigns a unique three-digit number to each class. Within each main class, additional digits are used to further classify the subject.

In this question, the call numbers consist of four components separated by dots: the main class number (813), the decimal (54), followed by letters and numbers to further categorize and differentiate the subjects.

To determine the correct order, we need to compare the main class numbers first, then the decimal numbers, and finally the letters/numbers at the end.

Let's analyze the given sets of call numbers:

A. 813.54 C78A, 813.54 C782A, 813.54 C780B, 813.54 C781D
B. 813.54 C782A, 813.54 C78A, 813.54 C780B, 813.54 C781D
C. 813.54 C781D, 813.54 C78A, 813.54 C782A, 813.54 C780B
D. 813.54 C78A, 813.54 C780B, 813.54 C781D, 813.54 C782A

First, we look at the main class number (813). It remains the same in all the sets.

Next, we compare the decimal numbers (54). Again, they are the same in all the sets.

Finally, we examine the letters/numbers at the end:

Set A: C78A, C782A, C780B, C781D
Set B: C782A, C78A, C780B, C781D
Set C: C781D, C78A, C782A, C780B
Set D: C78A, C780B, C781D, C782A

Comparing the letters in each set, we see that Set B (813.54 C782A, 813.54 C78A, 813.54 C780B, 813.54 C781D) is in correct order because the letters are arranged in ascending order (C78A, C780B, C781D, C782A).

Therefore, the correct answer is B. 813.54 C782A, 813.54 C78A, 813.54 C780B, 813.54 C781D.