Explain about Counterbalancing.

My teacher said this answer was wrong and I'm trying to understand how

When does Counterbalancing will be inappropriate?

I need more explanation on why second option is not possible?

What is the independent variable?

В (1,1) 3 2.aO .b O 2 1.dO

the Pellowing 11owin 2. 3- - 33= 1-ス 2.

C(11,8)=

Using the region names in the image below, select all regions that represent: An B'n C -B II VIII V IV VI VII A intersection not B intersection C. Region I: Items only in group A, not in B or C. Region II: Items in A and B, but not C. Region IlI: Items only in B, not in A or C. Region IV: Items in A and C, but not B. Region V: Items in A, B, and C. Region VI: Items in B and C, but not A. Region VIl: Items only in C, not in A or B. Region VIII: Items not in any of the groups.

Explain the principle of “avoid accidental activation”