A group of historians trying to give a factual account of the 1917 Russian Revolution finds a pamphlet published during that time by a communist group. This source is likely biased. What should the historians do with this source?

Use other sources to fact check the claims in the pamphlet.
Search for a more reliable source and ignore the pamphlet.
Present the pamphlet along with a source from a rival group.
Use the pamphlet but explain that it may include false information.

Use other sources to fact check the claims in the pamphlet.

Because they know that the pamphlet is biased, historians can use other primary sources from the time to fact-check the information given in the pamphlet, or simply to cast light on its claims.

Use the pamphlet but explain that it may include false information.

If the historians lack other sources from the period, they can simply present the pamphlet, clarifying that the source is biased and the information that it gives may be factually incorrect.