T-15: Billy owns several parcels of rental real estate, and he actively participates in managing the properties. His total loss from these activities in 2018 is $30,000 and his AGI for 2018 is $110,000. For how many years may any disallowed loss be carried forward?

a. The disallowed loss may not be carried forward.

b. The disallowed loss may be carried forward for 15 years.

c. The disallowed loss may be carried forward for 15 years, but only after it has been carried back for 3 years.

d. The disallowed loss may be carried forward indefinitely.

Please show your calculations. Thanks.