People in younger generations of the family
Children, grandchildren, nieces and nephews.
People in the possessor's care or under their authority
Students (of a teacher), employees (of a boss), patients (of a doctor or nurse)...
Pets, farm animals, zoo animals...
Not horses that are used for transport (See O-category 'transport')
Computers, phones, televisions, pens, books, knives and forks, balls, toys...
Not clothes and jewellery if they are worn or are on someone’s body
Large machines (not transport)
Machines such as cranes and bulldozers. Machines that are moved around and controlled or driven as part of their typical usage.
Nothing that is used for transport
Actions done by the 'possessor'
For example:
‘The talk of the expert’ (‘the experts talk’),
’The jump of the boy’ (’the boy’s jump')
‘The singing of the children' (‘the children’s singing')
In a nutshell, if we’re talking about a verb being done by someone or something, then that verb is ‘A’ category