Step-Up in Basis

Susan purchased stock many years ago for $80,000. At her death in 2026, the stock is worth $250,000. Her son inherits the shares and sells them three months later for $255,000. Ignoring any transaction costs, how much taxable capital gain must the son recognize?

1.  $5,000
2.  $80,000
3.  $170,000
4.  $175,000