Answer:
The correct comparative that fills the blank is:
- Mi mejor amiga es menos sociable que yo.
Step-by-step explanation:
The inferiority comparison is a usual way of mentioning that a noun (person, animal or thing) is lower in a characteristic that another noun, in Spanish, this type of comparison is made as mentioned below:
- Noun + conjugated verb "ser" + menos + adjective + que + noun.
In the case of the sentence provided, you already have the first noun that is "mi mejor amiga," the conjugated form of the verb "ser" that is "es," next must be used "menos," the adjective that is "sociable," the relative "que" and the last is the other noun, in this case, it is "yo."