The correct answer is (B) To interpret the meaning of poor or partially obliterated writing, or of anything that is difficult to understand or obscure, such as hieroglyphics. To convert transmitted in cipher into plain writing. To interpret by use of a key.

Examples of use:

• They were able to decipher the faded script only after a great deal of difficulty.
• Deciphering the enemy's communications constituted an important activity during the war.