251345
The series consists in three grade-based titles for preschool ( ages 2 to 4 ) , kindergarten ( ages 4 to 6 ) and first grade ( ages 5 to 7 ) .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None