According to Sec. 121, individuals who sell or exchange their personal residence may exclude part or all of the gain if the house was owned and occupied as a principal residence for

A) at least five years immediately before the sale date.

B) at least one year of the three-year period before the sale date.

C) at least two years of the five-year period before the sale date.

D) at least five years of the ten-year period before the sale date.