Correct option is C
As per the given statement, some part of Pigeon is Parrot. But, it can not be defined clearly in definite case that 'some part of Pigeon is not Parrot' or 'all part of Pigeon is Parrot'.
Hence, both conclusions are individually not follow but satisfying the 'either-or' case because:
1. Elements are same in both conclusions
2. Both conclusion are individually not follow
3. 'All & Some-not' is the complementary pair of either-or.
