Correct Answer - Option 2 : 3/8

__Concept:__

If an event E can occur in n(E) = k ways out of n(s) = n equally likely ways, then, \(\rm P \left( E \right) = \frac{{n\left( E \right)}}{{n\left( s \right)}} = \frac{k}{n}\).

__Calculation:__

The set, S = {HHH, HHT, HTH, THH, HTT, THT, TTH, TTT} is a sample space for the given experiment.

There are 8 elements in the sample space.

The possible outcomes is E = {HHT, HTH, THH}

n(E) = 3

Probability of obtaining two heads = \(\rm P \left( E \right) = \frac{{n\left( E \right)}}{{n\left( s \right)}} = \frac 3 8\)