Comparing acid strength of oxoacids derived from oxides
The question quoted in the OP is designed to test a periodic table trend concept.  

Particularly, within a given row of the periodic table, excluding noble gases, the element oxides form increasingly acidic aqueous solutions from left to right across the row.  

See the lecture by Dr. Pinkington The Acid-Base Character of Oxides and
Hydroxides in Aqueous Solution for additional information. 

Only answer (A) is increasingly acidic left to right across the periodic table.