Which of the following 5  implementations could not be used for getFrequency?

• public int getFrequencyOf(T anEntry) { int count = 0; for(int i = 0; i < numberOfEntries; i++) { if(anEntry.equals(contents[i])) { count++; } } return count; }
• public int getFrequencyOf(T anEntry) { int count = 0; for(int i = numberOfEntries - 1; i >= 0; i--) { if(anEntry.equals(contents[i])) { count++; } } return count; }
• public int getFrequencyOf(T anEntry) { int i = 0; int count = 0; while( i < numberOfEntries) { if(anEntry.equals(contents[i])) { count++; } i++; } return count; }
• public int getFrequencyOf(T anEntry) { int count = 0; for(int i = numberOfEntries - 1; i > -1; i--) { if(anEntry.equals(contents[i])) { count++; } } return count; }