Answer:
pelv/i/metry
Step-by-step explanation:
As we know, metry is the term which is often used for building words which are related to measurement. For example: geometry. Hence, using the word metry should be our first reliable option. As we are measuring the pelvis hence, we will use terms related to pelvis to form a complete word. Hence, by this perspective, pelvimetry is the best and most reliable option.