The Nagara style of temple architecture is characterized by its square or rectangular shape, a tower-like structure called shikhara, and the use of vertical ornamentation called ratha.

Option 1: Tigawa, Madhya Pradesh - This temple complex represents the Nagara style, as it has all the characteristic features mentioned above.

Option 2: Nachna, Rajasthan - This temple complex also represents the Nagara style, as it follows the same architectural features and design elements.

Option 3: Deogarh, Uttar Pradesh - This temple complex is known for its exquisite Nagara style architecture, with its shikharas and ornate sculptures.

Option 4: Mammalapuram, Tamil Nadu - Alert - correct answer should be option 4. Mammalapuram, also known as Mahabalipuram, does not represent the typical Nagara style. It follows the Dravidian style of temple architecture, which is characterized by its pyramidal shaped towers and detailed carvings rather than the square or rectangular shape of Nagara temples.

In conclusion, while all the other options represent the typical Nagara style, Mammalapuram stands apart with its Dravidian architectural style.