Explanation

Aridisols are not the most extensive soil order in Pakistan; Aridisols cover approximately 259,710 km2 according to some sources, but other orders like Entisols or Inceptisols might be larger. The exact figure for Aridisols is often cited as around 259,710 km2 in specific Pakistani soil surveys, making A potentially correct in that context. However, without a definitive authoritative source confirming Aridisols are the largest and the exact area, this requires verification.