Right option is (d) The choice of elements and mesh is problem-independent
To explain: A valid mesh can be coarse (i.e., have few elements) or refined(i.e., have many elements), and may consist of one or more orders and types of elements(e.g., linear and quadratic, triangular and quadrilateral). A judicious choice of element order and type could save computational cost while giving accurate results. It should be noted that the choice of elements and mesh is problem-dependent.