id say its a rhombus. all the other shapes can have right angles
B and D are correct. D is C and A aren't correct because a plane consists of three points.
Answer:
Step-by-step explanation:
E is the midpoint of Ac & D is the midpoint of AB
DE = (1/2)BC {Midpoint theorem}

2*x + 2*1 = 4x - 6
2x + 2 = 4x - 6
Add 6 to both sides
2x + 2 + 6 = 4x
2x + 8 = 4x
Subtract 2x from both sides
8 = 4x - 2x
2x = 8
Divide both sides by 2
x = 8/2
x = 4
2 i think that or 1 not 100% sure