Step 1: Understanding the Concept:
Newspapers often team up with foreign titles that have a similar focus. A business daily is likely to pair with a business newspaper abroad.
Step 2: Key Approach:
Sort the four names by their focus. Then see which one is a business paper and also known to have partnered with the Hindustan Times group in 2007.
Step 3: Sorting the names:
The Washington Post and the New York Times are general interest papers with strong political coverage. The Courier is a local title. The Wall Street Journal is the only one built around finance and business.
Step 4: Use the known fact:
HT Media started Mint in 2007 as a business paper for Indian readers. It tied up with the Wall Street Journal for a content sharing arrangement. This fits the focus test from the previous step.
Step 5: Reject the rest:
The Washington Post, the New York Times and the Courier are not linked with Mint in any such tie-up, so they cannot be the answer.
Final Answer:
The partner was the Wall Street Journal, printed as option 4. \[ \boxed{\text{Option 4}} \]