In this study unit, a child is considered a toddler between the ages of

 A. one and two years.B. one-and-a-half and three years.C. one and one-and-a-half years.D. one-and-a-half and two years.

 My Answer is B 

3 answers

I don't know what your study unit says.

However, according to these sources, your answer is wrong.

https://www.google.com/#q=toddler+age
Ok my answer is A
That seems to be the best answer.