year-year saving-total saving (inflaction adjusted)
1 - $827.88 - $827.88
2 - $803.77 - $1,631.65
3 - $780.36 - $2,412.00
4 - $757.63 - $3,169.63
5 - $735.56 - $3,905.19
6 - $714.14 - $4,619.33
7 - $693.34 - $5,312.66
therefore, if you live there more than 38 months, you should choose option 2 which is at the rate of 4.875, to compensate your $2600 closing cost.
If you assume the rate (comparing rate) is 12%, (so many people here bragged they can invest at this rate). then you have to live there for 42 months to compensate your $2600 closing cost