Statements:
No contract is a bond.
Some bonds are agreements.
All agreements are collaborations.
Some collaborations are obligations.
Conclusions:
I. Some bonds are not collaborations.
II. Some agreements are not contracts.
III. Some obligations are agreements.
IV. Some bonds are not contracts.
No contract is a bond (E) + Some bonds are agreements (I) = Some agreements are not contracts, hence conclusion II will follow. No contract is a bond. (E) ⟹ Some bonds are not contracts. (O) Hence conclusion IV will follow.