The correct option is C Coin shows tails
First let’s decide what will be the sample space of the experiment of tossing a coin once. It will be {H, T} as either head comes up or tails comes up.
So S = {H,T}
Now X = {H}
X’ or complement of X is everything in sample space except Heads.
So X’ = {H,T} - {H}
= {T}