Choice "b" is correct. Specific netting procedures for capital gains and losses are outlined in the Internal Revenue Code for non-corporate taxpayers. Gains and losses are netted within each tax rate group (e.g., the 15% rate group). The facts of this question have already performed this step for us.

Short-term Capital Gains and Losses

1. If there are any short-term capital losses (this includes any short-term capital loss carryovers), they are first offset against any short-term gains that would be taxable at the ordinary income rates.

2. Any remaining short-term capital loss is used to offset any long-term capital gains from the 28% rate group (e.g., collectibles).

3. Any remaining short-term capital loss is then used to offset any long-term gains from the 25% group (e.g., un-recaptured Section 1250 gains).

4. Any remaining short-term capital loss is used to offset any long-term capital gains applicable at the lower (e.g., 15%) tax rate.

Long-term Capital Gains and Losses

1. If there are any long-term capital losses (this includes any long-term capital loss carryovers) from the 28% rate group, they are first offset against any net gains from the 25% rate group and then against net gains from the 15% rate group.

2. If there are any long-term capital losses (this includes any long-term capital loss carryovers) from the 15% rate group, they are offset first against any net gains from the 28% rate group and then against net gains from the 25% rate group.

In this case, we are given net short-term capital losses of $70,000 to start with. Following the rules above, this first goes to offset any short-term gains at the ordinary income rates, but there are none in the facts. So, the next step is to offset the losses against any 28% rate gain long-term capital gains. The facts provide that there is $10,000 in gains from collectibles (taxable at the 28% rate). The remaining short-term loss ($60,000) is next used to offset the long-term capital gains at the 25% rate. The facts give us un-recaptured Section 1250 gains of $56,000 (taxed at the 25% tax rate). The remaining short-term capital loss is $4,000 ($70,000 - $10,000 - $56,000 = $4,000). The balance of the short-term capital losses is finally used to offset any capital gains taxed at the 15% tax rate, which the facts give us as $20,000. Therefore, after the $4,000 remaining short-term capital loss is applied to offset the $20,000 long-term capital gain taxed at the 15% tax rate, there is an amount of $16,000 remaining of long-term capital gains to be taxed at the 15% tax rate.

Choices "a", "d", and "c" are incorrect, per the ordering rules discussed above.