Concept:The ports authority manages port operations and provides essential services for cargo handling and storage.
Explanation:Ports authorities are responsible for the smooth functioning of seaports.
One of their key functions is to offer warehousing facilities for goods.
Warehousing means storing imported and exported goods safely before they are cleared or transported further.
Option A, enforcing law and order in harbors, is usually the duty of the police or port security.
Option B, collecting import duties, is a function of the customs authority.
Option D, checking the activities of smugglers, is also the work of customs and anti-smuggling agencies.
Therefore, among the given options, providing warehousing services is a genuine port authority function.
Answer:C. providing warehousing services