A bank has $400 million market value of commercial loans with an average duration of 0.40 years; $160 million market value of consumer loans with an average duration of 1.75 years; and $240 million market value of U.S. Treasury bonds with an average duration of 6 years. Calculate the bank's dollar-weighted asset portfolio duration?

3.5 years

3.7 years

2.35 years

2.9 years