Which of the following quadrilaterals is equiangular? Select the best answer from the choices provided.
A.
isosceles trapezoid
B.
parallelogram
C.
rhombus
D.
rectangle

Find the gradient of f(x, y,z)equals=left parenthesis x squared plus y squared plus z squared right parenthesis superscript negative 1 divided by 2 baseline plus ln left parenthesis x right parenthesis x2+y2+z2−1/2+ln(xyz) at the point left parenthesis negative 2 comma 1 comma negative 2 right parenthesis(−2,1,−2).