Final answer:
The 'End' key is used to move the cursor to the last field of the current record when navigating a main form, aiding in efficient data navigation.
Step-by-step explanation:
When navigating a main form, pressing B) End will move the cursor to the last field of the current record. This key is commonly used across various software applications to quickly navigate to the end of a line or a block of text. In the context of forms within databases or similar data entry programs, pressing the End key will take the user to the last field of the record that they are currently editing or viewing, thereby streamlining the data entry process.