Explanation: Computer security incident response team (CSIRT) is the organization that is responsible for helping others regarding the security of computers incidents that take place.They coordinate with other people of organization for being responsive and controlling the damage.
IT/Infosec(Information security) is the security that manages it through various tools. It protects the network ,application software etc.
The flow of CSIRT with IT/Infosec works in the upward direction that is maintaining the contact/communication by collecting the information and then taking action on it. Thus the correct option is option(c) and other option don't provide the correct direction for working.
