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Comprehensive and Detailed Explanation (150–250 words):

There are 5+4+3=125 + 4 + 3 = 12 marbles total. The probability the first draw is red is 5/125/12. After removing one red, there are 44 red and 1111 total marbles left. Thus, the conditional probability the second draw is red is 4/114/11. By the multiplication rule for dependent events, P(red then red)=(5/12)(4/11)=20/132=5/33P(\text{red then red}) = (5/12)(4/11) = 20/132 = 5/33. Option B (2/112/11) is a common mistake from dividing the remaining reds by the remaining total without accounting for the first draw’s probability. Option C (5/365/36) might arise from assuming independence and multiplying 5/12×5/125/12 \times 5/12, which is incorrect because draws without replacement are dependent. Option D (1/61/6) is a rough estimate that fails to handle dependence and exact counts. On the OAT, it’s critical to recognize when events are dependent (without replacement) versus independent (with replacement). Setting up these probabilities carefully—first event probability times the conditional probability of the second—ensures accurate calculation. The simplified fraction 5/335/33 is the exact probability.