An ideal gas occupying a volume of 2 dm³ and a pressure of 5 bar undergoes isothermal and irreversible expansion against external pressure of 1 bar. The final volume of the system and the work involved in the process is

• A

  10 dm³, 1000 J

• B

  8 dm³, –800 J

• C

  10 dm³, –800 J

• D

  10 m³, –1000 J