Rony Takes His Car to a Car Repair Workshop to Get

Rony takes his car to a car repair workshop to get it repaired. The cost of the repair has not been discussed beforehand in detail, although the cost in the nearby areas is normally around $1,000. After the repair, Rony and the mechanic agree on a bill of $800. Which of the following statements is correct?

A) A week after the repair, the mechanic sues Rony for a bill of $1,000.
B) After the repair, the mechanic agrees to give a discount of 10 percent. A week later, the mechanic sues Rony for a bill of $280.
C) A week after the repair, Rony sends a check of $100 marked "payment in full," which is encashed by the mechanic. A week later, the mechanic sues Rony for a bill of $700.
D) When Rony reaches home, the car's battery blows up due to an extra fitting made by the mechanic. Rony pays the mechanic just $100.
E) A week after the repair, Rony sends a check of $100 marked "payment in full," which is encashed by the mechanic. A week later, the mechanic sues Rony for a bill of $800.