B

Classical “rule of thirds” anthropometry divides the face into three roughly equal vertical segments—hairline to glabella, glabella to subnasale, and subnasale to menton—each accounting for about one-third (≈33 %) of total facial height, giving a proportion close to 34 : 33 : 33. Studies describing the neoclassical or Vitruvian facial canons reaffirm this equal-thirds concept of 33.3 % per segment [Naini et al., 2013, PMID 24009320; Borman et al., 1999, PMID 10096619].