The grammatically correct sentence is:
Las niñas son altas.
The other sentences contain grammatical errors due to subject-adjective agreement. "Niñas" (girls) is plural and feminine, so the adjectives should also be in the plural feminine form:
- Las niñas son pacientes. (for "patient" in plural, feminine)
- Las niñas son cansadas. (for "tired" in plural, feminine)
- Las niñas son serias. (for "serious" in plural, feminine)