Entities A, B and C have 60 per cent, 30 per cent and 10 per cent equity interests in entity D. Entity D has 10 board members, six from entity A, three from entity B and one from entity C. Each board member has one vote. Operational decisions require a 51 per cent majority. However, per the contractual agreement that governs entities A, B and C’s investment in entity D, strategic financing and operating decisions require each of entity A’s and entity B’s board members to unanimously agree. 

What is the relationship between A, B, C and D?