To answer this question, you need to have knowledge about the characters in the Mahabharata and the events of the Kurukshetra war.
Option A) Yuyutsu - This option is incorrect because Yuyutsu was not a warrior on the Pandava side and did not die on the first day of the war.
Option B) Abhimanyu - This option is incorrect because Abhimanyu, the son of Arjuna, was a warrior on the Pandava side and did die during the war, but not on the first day. He died on the 13th day of the war.
Option C) Uttar - This option is correct. Uttar was a warrior on the Pandava side and died on the first day of the war. He was killed by Shalya, the Kaurava's commander-in-chief.
Option D) Ghatotkacha - This option is incorrect because Ghatotkacha, the son of Bhima, was a warrior on the Pandava side and died during the war, but not on the first day. He died on the 14th day of the war.
Therefore, the correct answer is C) Uttar. He died on the first day of the war.