Quiz on נדרים מד

It seems Reisha is like Chachamim, and the Seifa is like R. Yosi is this true?
1. Yes.
2. No.
3. All Chachomim.
4. All R. Yosi.
5. Machlokes A&B.
This field is Hefker לשנה אחת לשבוע אחת may he retract?
1. Yes.
2. He always can.
3. No.
4. Machlokes A&B.
5. Machlokes A&C.
מפקיר את שדהו has only three days to retract.
1. True.
2. גזירה lest we forget the laws.
3. May retract anytime.
4. Machlokes A&B.
5. Machlokes A&C.
רבנן allow retraction here. Why?
1. Always allow.
2. Seriousness of the loss.
3. So that this can not be used as a loophole to get out of Ma'aser.
4. Kashya.
5. Machlokes A&C.
Why don't we worry that he will come to עשורי מן החיוב על הפטור?
1. He is a Chaver.
2. We warn him.
3. As it is so serious he is careful.
4. דאורייתא it is alright.
5. Machlokes A&D.