Test of choice for Reversible Myocardial Ischemia –
Nuclear cardiac imaging using radiotracers like Thallium is the first line technique for evaluating reversible ischemia.

It is worth noting that among the given options thallium scan is the best answer because PET is not provided as the option.
PET is the most accurate and gold standard for detection of reversible ischemia (hibernating myocardium).
Tests for detection of reversible ischemia (hibernating myocardium or myocardium viability) → PET (first choice), perfusion (thallium) scan (2" choice).
Thallium scan
MUGA scan
Resting ECHO
Coronary angiography