"Las" is the definite article for mochilas.
You use está because talking to teachers, older people, grandparents, or crowds should be formal
Answer: B)
Explanation: la pediatra in Spanish means Pediatrician in English. A Pediatrician is a doctor that takes care of children.
The correct Answer: Graciela nada los lines y corre los jueves. A ella le gustan los deportes.
Explanation: because the tense of the last line is correct.