Read the excerpt from act 2, scene 2, of The Tragedy of Julius Caesar and the background information on the allusion it contains. Excerpt:

[DECIUS.] It was a vision fair and fortunate.
Your statue spouting blood in many pipes,
In which so many smiling Romans bathed,
Signifies that from you great Rome shall suck
Reviving blood, and that great men shall press
For tinctures, stains, relics, and cognizance.
This by Calpurnia's dream is signified.

Background information:

In medieval times, it was customary to dip handkerchiefs into the blood of martyrs and other great people. Doing so turned the handkerchiefs into relics for worship or inspiration.

Why does Decius allude to "relics, and cognizance” in this passage?

to flatter Caesar and reassure him
to imply that Calpurnia is a sorceress
to warn Caesar of the plot against him
to prove that Calpurnia can see the future