Step 1: Recall the Fact:
The clue is the walk. A word that comes from toddling describes a child just learning to walk.
Step 2: Test each choice against this fact.
Choice 1 (Toddler): This name comes from toddling, the wobbly steps of a child who has just learned to walk, and the age is two to three years. It fits.
Choice 2 (Infant): This is for a child under one year, who is carried or crawls, so there is no jumpy walk. It is out.
Choice 3 (Teenager): This is a thirteen to nineteen year old, who walks like an adult. It is out.
Choice 4 (Adolescent): This word refers to a child going through puberty, so the age and the walk clue both fail. It is out.
Step 3: Cross-check the result.
Read the sentence once more with the chosen term in the blank. It should agree with the passage and with what is taught in the unit on early childhood care. Only one choice passes this test, and the other three each break one clear fact stated above. Each wrong choice names a different stage, place or person that does not match the clue in the question.
Final Answer:
The jumpy walking child of two to three years is a toddler, choice 1.
\[ \boxed{\text{Toddler}} \]