Answer:
A. 1/2
Explanation:
One way we can find which is less by comparing their decimal forms.
15/24 = 0.625
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1/2 = 0.5
7/8 = 0.875
19/24 = 0.79
6/8 = 0.75
1/2 is the only choice that is less than 0.625, aka 15:24. Therefore, that is the answer.
Additionally, I've answered this question before.
hope this helps :)