Statements : Some pastries are toffees. All toffees are chocolates. Conclusions : I. Some chocolates are toffees. II. Some toffees are not pastries.

Only conclusion I follows
Only conclusion II follows
Either I or II follows
Neither I nor II follows E. Both I and II follow

The correct answer is $\boxed{\text{E}}$.

Statement 1: Some pastries are toffees.

Statement 2: All toffees are chocolates.

Conclusion 1: Some chocolates are toffees.

This conclusion follows from Statement 1 and Statement 2. If some pastries are toffees, and all toffees are chocolates, then some pastries must be chocolates.

Conclusion 2: Some toffees are not pastries.

This conclusion also follows from Statement 1 and Statement 2. If some pastries are toffees, and all toffees are chocolates, then not all toffees can be pastries.

Therefore, both conclusions I and II follow.