Which two statements accurately describe the use of a symbolic index? (Choose two.)

Which two statements accurately describe the use of a symbolic index? (Choose two.)
A . <LAST> sets or retrieves an element value from the end of a value list or page list property.
B . <PREPEND> inserts a new element in a value list or page list property as the first element.
C . <APPEND> adds an element at a designated location in a value list or page list property.
D . <CURRENT> inserts a new element in a value list or page list property at the currently referenced index.

Answer: AB

Explanation:

Reference: https://community.pega.com/sites/default/files/help_v722/designer%20studio/expressionbuilder/ ref_refaggregateprop_symbolic.htm