Question: What song was sung by Arijit Singh in the 2016 Indian romantic drama film written and directed by Karan Johar?

Context articles: Agneepath (2012 film)
2 States (film)
Ae Dil Hai Mushkil
Ok Jaanu
Kal Ho Naa Ho
Muskurane
Soch Na Sake
Channa Mereya
Phir Bhi Tumko Chaahunga
Student of the Year

Agneepath (English: "The Path of Fire" ) is a 2012 Indian action drama film produced by Hiroo Yash Johar and Karan Johar under the banner of Dharma Productions.
 It is a retelling of the 1990 film of the same name and was directed by Johar's former assistant Karan Malhotra.
 The screenplay was written by Malhotra along with Ila Dutta Bedi.
 Johar pays tribute to his father, Yash Johar, the producer of the original, through the film.
 The music of the film was composed by Ajay-Atul, with lyrics written by Amitabh Bhattacharya.
 Though publicised as a remake, the film borrows only the basic plot of the original, while making the characters and incidents completely different.
 The film's title was taken from a poem of the same name by Harivansh Rai Bachchan, which forms a thematic link through the film, both literally and metaphorically.
2 States is a 2014 Indian romantic drama film co written and directed by Abhishek Varman based on the 2009 novel of the same name written by Chetan Bhagat.
 It is produced by Karan Johar and Sajid Nadiadwala.
 The film stars Arjun Kapoor and Alia Bhatt in lead roles.
 The film was released on 18 April 2014.
Ae Dil Hai Mushkil (English: "This Heart is Complicated" ) is a 2016 Indian romantic drama film written and directed by Karan Johar.
 It features Ranbir Kapoor, Anushka Sharma and Aishwarya Rai Bachchan in lead roles.
 It was released on 28 October 2016 on the Diwali weekend.
OK Jaanu (English: "OK Darling" ) is a 2017 Indian romantic drama film directed by Shaad Ali, story and screenplay by Mani Ratnam.
 Produced by Mani Ratnam and Karan Johar under their banners Madras Talkies and Dharma Productions respectively.
 The film stars Aditya Roy Kapur and Shraddha Kapoor in the lead roles, portraying a young couple in a live-in relationship in Mumbai with Naseeruddin Shah and Leela Samson play supporting roles as an older couple in the film, portraying the younger couple's landlords.
 Eesh Kakkkar plays Tara's ex-boyfriend.
 A. R. Rahman composed the film's score and soundtrack.
 Gulzar is the dialogue writer of this film.
 Gulzar has also written the lyrics for the songs in the film.
 It is an official remake of Mani Ratnam's Tamil film "O Kadhal Kanmani" starring Dulquer Salmaan and Nithya Menon.
Kal Ho Naa Ho (English: "Tomorrow May Never Come"), abbreviated as KHNH, is a 2003 Indian romantic drama, directed by debutant director Nikkhil Advani.
 The film was written by Niranjan Iyengar and Karan Johar and produced by Yash Johar and Karan Johar under their Dharma Productions banner.
 The soundtrack for the film was composed by Shankar-Ehsaan-Loy, with lyrics written by Javed Akhtar.
"Muskurane" (English: Smile) is a romantic Hindi song from the 2014 Bollywood film, "CityLights".
 Composed by Jeet Ganguly, the song is sung by Arijit Singh, with lyrics penned by Rashmi Singh.
 The music video of the track features actors Rajkummar Rao, Patralekha and Arijit Singh.
"Soch Na Sake" (English: ""Can't think of"") is a song from the 2016 Indian film "Airlift", an adapted version of Hardy Sandhu's ""Soch"", sung by Amaal Mallik, Arijit Singh and Tulsi Kumar.
 The lyrics for the song is written by Kumaar and the music is composed by Amaal Mallik.
 The song is a melodious mixture of Hindi and Punjabi lyrics.
 There is also a solo version of the song, sung by Arijit Singh.
"Channa Mereya" (English: "The light of my soul") is a song from the Indian film "Ae Dil Hai Mushkil".
 The song is penned by Amitabh Bhattacharya, composed by Pritam and sung by Arijit Singh.
 It was released on 29 September 2016 by Sony Music India.
"Phir Bhi Tumko Chaahunga" (English: "I will still love you") is a song from the Indian film "Half Girlfriend".
 Picturised on Shraddha Kapoor and Arjun Kapoor, the song has been sung by Arijit Singh and Shashaa Tirupati.
 The music of the song is composed by Mithoon and the lyrics are penned by Manoj Muntashir.
 Reprise version of the track is sung by Arijit Singh titled, "Pal Bhar (Chaahunga Reprise)", and also another version titled, "Phir Bhi Tumko Chaahungi" is sung by Shraddha Kapoor along with the instrumental "Half Girlfriend (Love Theme)".
Student of the Year is a 2012 Indian romantic comedy-drama film directed by Karan Johar and produced by Hiroo Yash Johar under the banner of Dharma Productions and in collaboration with Shah Rukh Khan's Red Chillies Entertainment.
 The movie features newcomers Sidharth Malhotra, Varun Dhawan and Alia Bhatt in the lead roles with Rishi Kapoor, Sana Saeed, Ronit Roy, Sahil Anand, Ram Kapoor and Farida Jalal in supporting roles.
 The movie also features Boman Irani, Kajol, Farah Khan and Vaibhavi Merchant in guest appearances.
 This is Karan Johar's first-and-only directorial venture without Shah Rukh Khan.