Which measurement is taken by looping a tape measure around the top of the bust?

The correct answer is bra/bust measurement because this measurement specifically refers to the circumference of the bust area, which is determined by looping a tape measure around the fullest part of the bust. This technique provides a precise measurement that is essential for determining the correct bra size and ensuring proper fit in clothing designed for the upper body.

In the context of garment fitting and sizing, the other options do not pertain to the bust area at all. The waist measurement is taken around the narrowest part of the torso, typically just above the belly button. The hip measurement is taken around the fullest part of the hips and is important for fitting trousers and skirts. The pants inseam measures the length of the inside leg from the crotch to the bottom of the hem, which is unrelated to the bust or bra sizing. Therefore, the choice of bra/bust measurement accurately reflects the action described in the question.