The term "between-subjects" refers to

a. observing the same participants in each group
b. observing different participants one time in each group
c. the type of post hoc test conducted
d. the type of effect size estimate measured

b. observing different participants one time in each group

If we analyze the formula for the sum of squares between we see that we are subtracting the mean for each group minus the grand mean. But in order to find the mean of each group we just need to observe just one time the dependent variable of interest for each group.

Step-by-step explanation:

Previous concepts

Analysis of variance (ANOVA) "is used to analyze the differences among group means in a sample".

The sum of squares "is the sum of the square of variation, where variation is defined as the spread between each individual value and the grand mean"

Solution to the problem

If we assume that we have groups and on each group from we have individuals on each group we can define the following formulas of variation:  

If we analyze the formula for the sum of squares between we see that we are subtracting the mean for each group minus the grand mean. But in order to find the mean of each group we just need to observe just one time the dependent variable of interest for each group.

For this reason the best option on this case is:

b. observing different participants one time in each group

And we have this property :

step-by-step explanation:

it will be a cylinder. with a diameter of 8 and 4 single pieces high