Not only can you pick from three index option periods (5, 7, or 10 years, subject to availability), but you also have up to three choices of indexes. (jackson.com)
See if you can get a longer option period by paying a higher option fee. (biggerpockets.com)
This lease option period typically varies from 1 - 3 years, during which time the tenant / buyer can exercise his / her right to purchase. (foreclosureuniversity.com)