D obtained a loan of P5,000.00 from C. The obligation is secured by a pledge of D's ring which he delivered to C. Both the loan and the pledge were in a private instrument. While the loan was outstanding, D sold the ring through a public instrument to X who was not aware of the pledge. Under the deed of sale, D obliged himself to deliver the ring physically to X after a week. Before X could obtain actual delivery of the ring, he learned that D had earlier pledged the same and that C was selling the ring in a public sale because of D's default in the payment of his debt.

a. C can sell the ring to satisfy his claim

b. X did not acquire ownership of the ring from D

c. X is not bound by the pledge made by D to C

d. X is bound by the pledge made by D to C