Correct Answer - Option 2 : Somya
Five persons - Sunny, Swati, Somya, Surbhi and Sapna.
1. Swati was elder to Somya but younger to Sunny.
Sunny > Swati > Somya
2. Surbhi was elder to Sunny who was elder to Sapna who was not the youngest.
Surbhi > Sunny > Sapna > __
From 1 and 2, we get two possible cases:
Case I: Surbhi > Sunny > Sapna > Swati > Somya
Case II: Surbhi > Sunny > Swati > Sapna > Somya
Clearly, from both the cases, 'Somya' is the youngest.
Hence, ‘Somya’ is the correct answer.