Practice exam with wrong answer?

I came across this sample practice exam.
http://www.ipass4sure.com/demopdf/MB7-702.pdf

I am fairly new in Navision so I would like to get some experts' comments on this.
Please have a look at question #1 and its given answer.

QUESTION: 1
You are designing a table with a Customer Name field that must not be stored.
The table must derive its contents from the Name field on the Customer table. The
Customer Name field must then be used in a C/AL function. How should you
create the Customer Name field and then access it using C/AL code?
A. Create the Customer Name as a FlowFilter field. In the code, use the
CALSUMS function to evaluate the value of Customer Name.
B. Create the Customer Name as a Normal text field. In the code, use the
EVALUATE function to evaluate the value of Customer Name.
C. Create the Customer Name as a FlowField with a Method set to Lookup. In the
code, use the CALCFIELDS function to evaluate the value of the Customer Name.
D. Create the Customer Name as a FlowFilter field. In the code, use the
EVALUATE function to evaluate the value of Customer Name.

I really doubt that the answer given (A) is correct, because from what I understand, CALSUMS is only used to calculate the total of SumIndexFields which is numeric, how do you evaluate the Customer Name using this method?
Somehow I think that the correct answer here is C?

However if the answer is really A, can someone explain a little bit?
Thank you.