17 (D) P authorized A to sell P's land, the purchase price payable to P in 12 monthly installments. A sold the land to X. In this case, P knowingly permits A to collect from X, what is the authority of the agent ? A. express C. estoppel B. Specific D. apparent 18. Going back to item No.17, assuming A collects from X without informing P but under such circumstances as to charge P with knowledge of such collection, as that several months have already passed, what is the authority of the agent? A. express C. estoppel B. Specific D. apparent 19. Authority of the agent founded on the negligence of the principal. A. express C. estoppel B. Specific D. apparent 20. Authority of the agent though not actually authorized and yet the principal permits the agent to continue do perform the same. A. express C. estoppel B. Specific D. apparent 21. The third party knows that the agent is acting for the principal. A. Partially disclosed C. Undisclosed B. Disclosed D. Implied 22. The third party knows that the agent is acting for the principal but does not know the identity of the principal A. Partially disclosed C. Undisclosed B. Disclosed D. Implied