Correct Answer - Option 3 : 1/2

**Given:**

Number of unbiased coin = 3

**Calculation:**

Total number of results when three coins are tossed = 2^{3} = 8

Favourable result = (TTH, THT, HTT, TTT)

Number of favourable results = 4

∴ Probability of at least two heads = 4/8 = 1/2