Explanation:

URL stands for Uniform Resource Locator. It is a reference (an address) to a web resource that specifies its location on a computer network and a mechanism for retrieving it. URLs are fundamental for navigating the internet. Option (1) and (4) are incorrect as 'Research' or 'University' are not part of the standard acronym. Option (3) 'Universal Resource Locator' is a common misconception; while widely used, 'Uniform' is the technically correct and standardized term, emphasizing the consistent format.