Pat sells real estate for $30,000 cash and $120,000 5-year note. If her basis in the property is $90,000 and she receives only the $30,000 down payment in the year of the sale, how much is Pat's taxable gain in the year of sale using the instalment sales method?
A. $60,000
B. $30,000
C. $15,000
D. $12,000
E. $0