Correct answer: c) Short axis by 2D
As per the ESC (European Society of Cardiology) 2014 guidelines, short axis 2 dimensional (2D) measurements of all LV segments from base to apex is recommended to measure the maximum thickness of the left ventricular wall in hypertrophic cardiomyopathy. LV maximum thickness is a factor used for risk stratification with a cut off value of 30 millimeters.
Measurement of LV thickness by M-Mode in parasternal long axis view, which is the most common method of LV measurements, is likely to give erroneous results due to oblique cuts. Moreover it will miss out localized hypertrophy as in apical variety of HCM.