Any help on this question?

Which of the following pairs of biblical symbols stand for divinely sanctioned authority?

a. lamb and dove
b. nimbus and orant figure
c. keys and chi-rho symbol
d. palm leaves and shepard

I'm really not sure so any direction or assistance would be helpful. It doesn't seem to be answered anywhere in my textbook.

I think it's b. Check your book or Google those two words.