How Long and Often Should "Freeplay" Time with Manipulatives Be

Multiple Choice

How long and often should "freeplay" time with manipulatives be given, accordingto the author in Chapter 9?

A) About 5 minutes the first time students use them.
B) 5-10 minutes at the end of the period, when appropriate.
C) 15-20 minutes the first time students use them.
D) 15-20 minutes at the end of the period, when appropriate.
E) One class period the first time students use them.