Assume that the SUBSTRING (a, b) command can be used to produce a substring of a String where a is the index of the first letter in the substring and b is the index of the last letter in the substring. Assume that the index of the first letter in a string is 1. Here’s an example of how SUBSTRING can be used: x ← “I have not the pleasure of understanding you.” x SUBSTRING (1, 10) This code fragment would create the substring “I have not”. The following procedure takes four parameters: a full name, a number representing the length of the first name, a number representing the length of the middle name, and a number representing the length of the last name. The procedure returns just the first name. PROCEDURE firstName (fullName, fLength, mLength, lLength) { RETURN ← //code needed to replace this comment// } If fullName was set to "Jane Marie Smith", the procedure would return "Jane". Which of the following should replace the comment in the firstName procedure so that it works as intended?