Answer : 3. "Lucknow"
Explanation :

Prime Minister Shri Narendra Modi inaugurated the 'Azadi@75 - New Urban India: Transforming Urban Landscape' conference-cum-expo on 5 October 2021 at 10:30 am at Indira Gandhi Pratisthan, Lucknow, Uttar Pradesh.

The Prime Minister will digitally hand over the keys of Pradhan Mantri Awas Yojana – Urban (PMAY-U) houses to 75,000 beneficiaries in 75 districts of Uttar Pradesh and will also virtually interact with the beneficiaries of the scheme in Uttar Pradesh. He will inaugurate/lay foundation stone of 75 urban development projects of Uttar Pradesh under Smart City Mission and AMRUT; Flagged off 75 buses under FAME-II for seven cities including Lucknow, Kanpur, Varanasi, Prayagraj, Gorakhpur, Jhansi and Ghaziabad; and released a coffee table book covering 75 projects implemented under various key missions of the Ministry of Housing and Urban Affairs, Government of India. He will also visit three exhibitions being organized in the expo. The Prime Minister will also announce the establishment of Shri Atal Bihari Vajpayee Chair at Babasaheb Bhimrao Ambedkar University (BBAU), Lucknow.

On this occasion, the Governor and Chief Minister of Uttar Pradesh including the Union Defense Minister, Union Housing and Urban Affairs Minister will be present.