Question

electricity from fusion nuclear energy
is not possible.
accounts for less than 15 percent of current world electricity production.
has been achieved, but is not yet practical.
has been increasing for the past seventy years.

Explanation:

Nuclear fusion has been achieved in experimental settings (like in tokamaks), but there are still challenges such as achieving a net - energy gain (where the energy output is more than the energy input for sustaining the fusion reaction) and developing a practical, commercial - scale reactor. So, it is not yet practical for large - scale electricity generation.

Answer:

has been achieved, but is not yet practical.