There are 3 pronouns for people
she/her
he/him
they/there
Sabe is the answer. It means knows
The question asks you to conjugate the verb "ser" for first person singular (yo).
The correct form is: :"soy"
The full sentence:
Yo soy alta.
The full paradigm of "ser" is:
yo soy
tu eres
el/ella es
nosotros/nosotras somos
vosotros/vosotras sois
ellos son
Son palabras como el, ella, ellos. Enves de decir el nombre de la persona dices el o ella.