Step 1: Horizontal reservation.
Reservation for women cuts across all categories and is therefore classified as horizontal reservation.
Step 2: Vertical reservation.
Vertical reservation applies to socially and educationally backward classes such as SC, ST, and OBC. Hence, women reservation is not vertical.
Step 3: Reservation for OBC.
Reservation for OBC is vertical, not horizontal. Therefore, statement (iii) is incorrect.
Step 4: Conclusion.
Only statement (i) is true. Hence, the correct answer is (C).