Final answer:
Points B (-5,15), C (1,10), and D (7,8) satisfy the given inequalities and are inside the shaded region. However, clarification may be needed if there's a typo or additional context to determine a single correct answer among the given options.
Step-by-step explanation:
To find which point (s,t) is inside the shaded region represented by the given set of inequalities, check each point against the inequalities s ≤ 12 and t > 0.
Therefore, points B (-5,15), C (1,10), and D (7,8) are all inside the shaded region. However, since the question suggests there's only one correct answer, there may have been a typo or misinterpretation. If we strictly answer according to the presented options, we could suggest the proper points among the ones given, but we would need more context to provide a single definitive answer.