For such a company, I would choose functional structure because the company has grouped the activities or jobs of similar nature into separate departments, such as manufacturing, finance, marketing and so on.
Advantages of functional structure
Functional structure has the following advantages:
(i) It leads to occupational specialisation, since emphasis is placed on specific functions and repeated performance leading to efficient functioning.
(ii) It promotes control and coordination within a department because of similarity in the tasks performed.
(iii) It leads to increased efficiency and profits.
(iv) It leads to minimal duplication of efforts, which results in economies of scale, and this lowers the cost.
(v) It makes training of employees easier as the focus is only on a limited range of skills.
(vi) It ensures that all functions get due attention. 

Delegation refers to the transfer of authority from superior to subordinate for the completion of the tasks. It is a key element in effective organising because of its benefits.
Importance of delegation
 Delegation is a key element in effective organising because 
(i) It leads to effective management, since the manager by delegating the routine jobs to the subordinates, is able to focus on other important decisions.
(ii) Delegating work to subordinates, gives them a sense of recognition and motivates them to work efficiently and responsibly.
(iii) There is a better coordination, as the authority, responsibly and accountability are properly defined and there is no chaos and overlapping of activities.

It is a network of personal and social relations, not established or required by the formal organisation but arising spontaneously as people associate with each other. e.g. chit chatting in a canteen, formation of drama group by employees, etc.