Explanation:

- Correct Answer: Option 1, Bajaura Temple

- The Bajaura Temple, also known as the Basheshwar Mahadev Temple, in Kullu district is one of the earliest examples of 'Nagara' style architecture.

- Built around the 8th century, it showcases distinctive Nagara characteristics like a tall curved spire.

- Option 2, Baijnath Temple

- This temple, dedicated to Lord Shiva, exemplifies later developments in Nagara design.

- It was constructed in the 13th century and is renowned for its elegance.

- Option 3, Jwala Mukhi Temple

- This temple is famous for its eternal flame, not for its architectural style.

- It’s significant for its religious importance rather than architectural design.

- Option 4, Masrur Temple

- These rock-cut temples are remarkable but represent a different variant of temple architecture.

- Dated to the 8th century, they are not the earliest Nagara specimens.