Henry owns a qualified farm operation. The ACB of the farm is $$500,000.$ He sold the property for $$900,000.$ He never utilized the lifetime capital gains exemption of $$950,000.$ How much taxable capital gains he has to report?

a$.$ $$200,000$

b$.$ $$400,000$

c$.$ $$0$

d$.$ $$100,000$