Based on the question stem and the autoanitbodies given (butterfly rash combined with anti-dsDNA/anti-Sm/antiphospholipid), this woman has classic lupus. SLE is associated with cytopenias, so thrombocytopenia is the best choice of the available answers. Thrombocytopenia is common in lupus (FA2020 p470)

• HUS is associated with E.coli or Shigella infection and not Lupus. Lupus kidney disease is diffuse proliferative glomerulonephritis.
• Macrocytic anemia is typically caused by B12 or folate deficiency and not associated with lupus. Lupus anemia is typically anemia of chronic disease, which is normocytic, or due to inadequate RBC production or iron deficiency, which is microcytic.
• Multiple nucleated erythrocytes are found in leukemias when the RBCs are being "pushed" out of the bone marrow, or in diseases where the bone marrow is highly stressed. Lupus does not typically cause this.
• I am not 100% sure why rouleax formation is wrong, because as far as I understand any condition that increases monoclonal Abs can cause rouleaux formation, but I am assuming it is just not as common/likely, hence thrombocytopenia which is very common is the better answer