Commercial power generation from fusion reactor is not yet possible,
because
(A) It is difficult to control nuclear fusion reaction
(B) The fuel required (i.e., deuterium & tritium) is scarce
(C) It is difficult to initiate fusion reaction
(D) Quantity of fuel required for initiating fusion reaction is prohibitively
high
because
(A) It is difficult to control nuclear fusion reaction
(B) The fuel required (i.e., deuterium & tritium) is scarce
(C) It is difficult to initiate fusion reaction
(D) Quantity of fuel required for initiating fusion reaction is prohibitively
high