A fair die is rolled. The probability of getting an ODD number is

1. Sample space: $S = \{1, 2, 3, 4, 5, 6\}$, with 6 equally likely outcomes. 2. Event 'odd number': $E = \{1, 3, 5\}$, with $|E| = 3$ outcomes. 3. $P(E) = 3/6 = 1/2$. 4. Equivalently, half the outcomes are odd → probability is $1/2$, an intuitive answer. 5. Option A is for ONE specific number (like $P(\text{rolling 5}) = 1/6$). Option B is for two specific values out of six. Option D is the probability of NOT being odd (i.e., being even), which is the same $1/2$ — but we're asked for odd, not even. _Source: NCERT Class 11 Mathematics, Ch 14, §14.2.2 (Equally likely outcomes — die examples), p. 7–8._