Question main service grounding

[hhsting]

Please see attached sketch. I have listed assembly MLO main service switchboard fed from one utility service.

The plans show one grounding electrode conductor from each of the main service breakers in switchboard going to ground bus bar.


I am little confused here for listed assembly i know code allows one main bonding jumper however where does it say in NEC 2017 one grounding electrode conductor is permitted or multiple?

 

[infinity]

What you have shown is code compliant. I see no need to run 4 GEC's when you can run just one to the first section on the left.