The answer is D. d-12 ≥ 51; d ≥ 63 because it shows d, dollars in your bank account, minus 12, which represents the $12 spent. If you have at least 51 left, then the amount must be greater or equal to 51. And d must be greater than or equal to 63 because that is the least amount you have left + the 12 you spent!
