Or possibly easier to maintain if you split into 2 cells e.g. in P2

=INDEX($B$2:$E$2,MATCH(MIN(B31:E31),B31:E31,0))

then in another cell

=IF(P2>3,INDEX(N$2:N$10002,MATCH(LEFT($A31,P2),INDEX(J$2:M$10002,0,P2-3),0)),"ABC")