Correct option is: A) \(\frac{7}{8}\)
When three coins are tossed simultaneously once.
Then total possible outcomes are
{HHH, HHT, HTH, THH, HTT, THT, TTH, TTT}
\(\therefore\) Total possible outcomes is n (S) = 8
Favourable outcomes to the even of getting at least one tail are
{HHT, HTH, THH, HTT, THT, TTH, TTT}
\(\therefore\) Total No of favourable outcomes = 7
\(\therefore\) Probability of getting at least one tail
= \(\frac {Total \,No\, of \,favourable \,outcomes}{Total \,Possible \, outcomes}\)
= \(\frac 78\)
Hence, probability of getting at least one tail is \(\frac 78\)