{ 1 } - deducing OUGHT from IS.
{ 2 } - deducing IS from OUGHT.
{ 3 } - both of the above.
{ 4 } - none of the above.

Hume's Law claims that you can't deduce an OUGHT from an IS. If you conclusion has "ought," then your premises must also have "ought" or similar terms. You can't prove moral conclusions from purely non-moral premises.

Most philosophers think that Hume held Hume's Law. But some doubt this.