If there is no primary key field, then the data is sorted ________

Consider a class that uses the following variables to implement an array-based stack:

``` String [] s = new String[100]; int top = -1; // Note top == -1 indicates stack is empty ``` a method that implements a String peek() operation can be written as A) if (top == -1) throw new RuntimeException("Empty Stack"); else return s[top -1]; B) if (top > -1) return s[top]; else throw new RuntimeException("Empty Stack"); C) top--; if (top == -1) throw new RuntimeException("Empty Stack"); else return s[top]; D) if (top == 0) throw new RuntimeException("Empty Stack"); else { top--; return s[top]; }

A(n) ____________________ report repeats information in more than one column on the page.

Fill in the blank(s) with the appropriate word(s).