Which track is playing in S2E1 of Ansatsu Kyoushitsu? In the 1st episode of Ansatsu Kyoushitsu [Assassination Classroom] season 2,
an instrumental track plays in the background from 5:20 to 5:50. If anyone knows its name, please tell me.
This is "Irina no Koigokoro", which is track 5 on the special CD bundled with S2 BD2 (EYXA-10829B). Here is a 15-second extract from the beginning of the track. 

Seems like an odd piece to be playing in a sequence where Karma and Manami are talking (not about Irina), but it is what it is.