Conjugations of verbs for the formal "you" in Spanish are the same as for the subjects el and ella; in present tense, they usually end in -a.
The option you have checked is in past tense ("I bought this"); the present tense conjugation is compra.
Usted compra esto.
Again, the conjugation of verbs for the formal "you" in present tense almost always end in the letter "a"; the correct conjugation is estudia.
Usted estudia <span>matemáticas.</span>
What is the question? That's literally only a story there.
A.
9/3 <em>el nueve de marzo</em>
5/7 <em>el quinto de julio</em>
4/9 <em>el cuarto de septiembre</em>
8/11 <em>el ocho de noviembre</em>
1/1 <em>el uno de enero</em>