Tiana's Father Gives Her a Few Blocks and Cubes to Play

Tiana's father gives her a few blocks and cubes to play with. She plays with them for a while and manages to place three red cubes on top of two blue cubes and build a tower. She is excited to show the colorful tower to her father. In the context of key milestones in the first 3 years of life, Tiana is most likely

A) 5 months old.
B) 7 months old.
C) 10 months old.
D) 15 months old.