First off option strikes are usually in $2.50 or $5 increments. For instance right now Visa (V) has the following strikes available for April expiration: 45, 50, 55, 57.50, 60, 62.50, 65, 67.50, 70, 72.50, and 75 (there might be more above 75 or below 45 but no more in between). This means...