A bought a parcel of land from B on installment. When the first installment fell due, A did not pay. His defense was that he did not have available money, and he therefore pleaded impossibility of performance.

A is liable because the obligation is to pay money which is determinate.

A is liable. A mere pecuniary inability to fulfill an engagement does not discharge the obligation of the contract.

A obligation is extinguished because of impossibility of performance.

A obligation is extinguished because A has no available money.