All of Company A's shareholders are private individuals. Company A owns shares which gives it control of 75% of the voting power in Company B as well as shares that gives it control of 52% of the voting power in Company D. In turn, Company B owns shares which gives It control of 49% of the voting power in Company C. However, under a shareholders' agreement with all other shareholders of Company C, Company B has the right to decide on the composition of Company C's board of directors. (Please see section 5 of the Companies Act)

Explain, with reference to relevant sections of the Companies Act whether, and if so, how the following companies are related:

Company A and Company B

Company A and company C

Company C and Company D.