In the ICF Framework, the Four Primary Domains Are Identified

In the ICF framework, the four primary domains are identified by letters, which are followed by a series of numbers.What does the first letter and the first number represent ?

A) b denotes the domain and 7 the subcategory of the identified function
B) b denotes the domain and 7 identifies the chapter of the functional activity
C) b denotes the subcategory and 7 the activities and participation domain
D) b denotes the level of impairment and 7 the domain