Test execution monitoring requires metrics that show testing progress and results in real-time. Option D is correct because test cases run/not run and passed/failed are direct execution metrics that indicate: what portion of planned testing is complete, and what portion of executed tests passed. These metrics help track progress, identify blockages, and assess product quality during execution. Options A, B, and C describe useful metrics but they're either post-execution (residual defects), planning-phase metrics (test case preparation), or cost tracking rather than execution monitoring.