The answer is C because in French there is something called le COD and Le COI le COD is the doctor which is replaced by Le but there is no COI in this sentence
<span>My opinion about the people who boast in French have their crown
</span>Translated to english
Explanation:
1 c'est une grande voiture
2 il est petit
3 c'est une prof intéressant
4 c'est une belle maison