Solution

     There are 3 problems ( 1,2,3 ) which have two solutions.

Problem 1. O1,Q2,L2,K1,M1 

Problem 2. Q2,Q1,P1,Q2,S2

Problem 3. Life or Capture ? (T5, T3, T4 )

Problem 4. Snapback (P1,T5,S3,N1,O1,M1,P3,P2,P4,Q1,O1 ). Though white can make it ko, black has advantage for ko ( P1,T5,S3, then T3,T2,S4 )

Problem 5. ? Mark ( L11,K10,L10,K9,L9,K12,M12).