Answer:
The correct answer is option<u><em> b. haga. </em></u>
Explanation:
As Juanito's dad wants him to do his homework with excellence, this sentence is referring to an imperative form in the present subjunctive using subordinated sentences.
The way to conjugate correctly the verb is by identifying the <em>principal sentence</em>, which can be in indicative or subjunctive tense, in this case: <em>"El papá de Juanito exige"</em>, in which the subject <em>(El papá de Juanito)</em> and the verb<em> (exige)</em> agree in number and person for the present simple (indicative) for the third person singular has a termination -e.
And then goes the <em>subordinate sentence</em>, in this goes the verb in present subjunctive, that has to be conjugated accordingly to the <em>indirect object,</em> the one in which the action from the principal sentence relies on (the answer to the next question gives us the indirect object: who is demanding Juanito's dad to do their homework with excellence?). In this case: Juanito, which is third person singular (he/she), which in present subjunctive the termination is "a". For this reason, option<em> a. HAGAN is not correct</em> because it is conjugated for the third person <u>plural</u>, and therefore does not agree with the indirect object.
With the verb <em>"hacer"</em>, root is "<em>hac</em>", but as an irregular verb a letter "g" is introduce instead of the "c" in order to make a better sound in the conjugations, for that reason <em>option d. HACA is not correct</em>. Nor option c. <em>HACAN,</em> which would be the plural version of option d.
Moreover, the verb goes = HA + G+ A. Therefore, <em><u>the correct answer is option B. HAGA.</u></em>
