Step 1: Understand the question.
The question asks for the person who hears and settles complaints from readers about a newspaper.
Step 2: Recall the idea.
Some newspapers appoint an independent person to look into reader complaints about accuracy and fairness. This post is called an ombudsman, or readers' editor.
Step 3: Check option 1, Wire Editor.
A wire editor selects and edits stories that come from news agencies. This is not a complaints role, so it is wrong.
Step 4: Check option 2, Sub-Editor.
A sub-editor corrects copy, writes headlines and fits stories to pages. Not a complaints role, so it is wrong.
Step 5: Check option 3, Reporter.
A reporter collects and writes news. A reporter is often the subject of a complaint, so cannot judge it. This is wrong.
Step 6: Check option 4, Ombudsman.
An ombudsman receives complaints, examines them independently and recommends or publishes corrections. So option 4 is right.
Final Answer:
The ombudsman arbitrates complaints. This is option 4.
\[ \boxed{\text{Ombudsman (Option 4)}} \]