Final answer:
The sum rule of probability states that the probability of two mutually exclusive events happening is the sum of their individual probabilities. Hence the correct answer is option B
Step-by-step explanation:
The sum rule of probability states that the probability of two mutually exclusive events happening is the sum of their individual probabilities. This rule is used when considering two outcomes that can happen in different ways. For example, if you are flipping a penny and a quarter, the probability of getting one coin heads and the other coin tails can be calculated by [(PH) × (QT)] + [(QH) × (PT)] = [(1/2) × (1/2)] + [(1/2) × (1/2)] = 1/2.
Hence the correct answer is option B