Commercial scale production of hydrogen from iron-steam reaction represented by, 3Fe + 3H2O = Fe3O4 + 4H2, is not practised, as it is __________________?

• A. A slow reaction
• B. A discontinuous reaction (requiring regeneration of iron by water gas intermittently)
• C. Still in development stage (by employing fluidised bed technique)
• D. All A , B. and C