Heidi Bought a Mountain Chalet in 2015 for $150,000 and Sold

Heidi bought a mountain chalet in 2015 for $150,000 and sold it in 2020 for $180,000. She bought a lakeside cabin in 2016 for $100,000 and sold it in 2020 for $130,000. She lived full-time at the chalet in 2015 and spent an equal amount of time at the chalet and the cabin during the 5 years from 2016 to 2020. How should she allocate her principal residence gain reduction for the year 2016 to minimize her 2020 taxable capital gains?

A) 2016 should be allocated to the cabin
B) 2016 should be allocated to the chalet
C) 2016 should be split between the cabin and the chalet
D) 2016 cannot be allocated to either the cabin or the chalet