Ok, I think I understand what you're going for. Is it something like this?

To do this I would approach it similarly to my last post, using pivot_longer() to keep the treatment groups as a single column:
library(tidyverse)
# Build a snapshot of the dataset
trials <- tribble(
~NO, ~A, ~B, ~C, ~D, ~E,
42, "Yes", "No", "No",6, "No",
12, "Yes", "No", "No",2, "Yes",
43, "No", "No", "No",13, "Yes",
4, "Yes", "No", "No",1, "Yes",
44, "No", "No", "No",5, "Yes",
42, "No", "No", "No",1, "Yes",
12, "No", "No", "No",6, "Yes",
43, "Yes", "No", "No",3, "Yes",
4, "No", "No", "No",0, "Yes",
44, "Yes", "No", "No",9, "Yes",
30, "Yes", "No", "No",3, "Yes",
38, "No", "No", "No",5, "Yes",
58, "Yes", "No", "No",1, "Yes",
46, "Yes", "No", "No",3, "No",
31, "No", "No", "No",12, "Yes",
30, "No", "No", "No",4, "Yes",
38, "Yes", "No", "No",8, "Yes",
58, "No", "No", "No",7, "Yes",
46, "No", "No", "No",5, "Yes",
31, "Yes", "No", "No",2, "Yes",
30, "No", "No", "Yes",4, "No",
38, "Yes", "No", "Yes",6, "Yes",
58, "Yes", "No", "Yes",4, "No",
46, "Yes", "No", "Yes",2, "Yes",
31, "No", "No", "Yes",6, "Yes",
30, "Yes", "No", "Yes",3, "Yes",
38, "No", "No", "Yes",3, "Yes",
58, "No", "No", "Yes",4, "Yes",
46, "No", "No", "Yes",5, "Yes",
31, "Yes", "No", "Yes",7, "No",
42, "No", "No", "Yes",3, "No",
12, "Yes", "No", "Yes",10, "Yes",
43, "No", "No", "Yes",9, "Yes"
)
# Pivot to long format so that we can use separate colors for treatment groups
# and have all "Yes/No" boxplots in the same place
long_df <- trials %>%
pivot_longer(names_to = "trt_group", values_to = "treated",
c(A, B, C))
# Now plot. Fill = trt_group changes the boxplot fill color based on the
# treatment group it was assigned. Yes/No is still the x-axis
long_df %>%
ggplot() +
geom_boxplot(aes(x = treated, y = D, fill = trt_group))

# You can use two lines of fake data to adjust the width of the boxplot so that
# the missing B group is still accoutned for. Taken from here:
# https://stackoverflow.com/questions/15367762/include-space-for-missing-factor-level-used-in-fill-aesthetics-in-geom-boxplot/15368879#15368879
long_df %>%
add_row(D = c(50, 60), E = c("Yes", "Yes"), trt_group = c("B", "C"),
treated = c("Yes", "Yes")) %>%
ggplot() +
geom_boxplot(aes(x = treated, y = D, fill = trt_group)) +
coord_cartesian(ylim = range(long_df$D) + c(-.25, .25))

# And finally you can customize the plot
long_df %>%
add_row(D = c(50, 60), E = c("Yes", "Yes"), trt_group = c("B", "C"),
treated = c("Yes", "Yes")) %>%
ggplot() +
geom_boxplot(aes(x = treated, y = D, fill = trt_group)) +
coord_cartesian(ylim = range(long_df$D) + c(-.25, .25)) +
xlab("Received treatment") +
ylab("Count of behavior observations") +
scale_fill_discrete(name = "Treatment Group") +
theme_bw()

Created on 2021-07-28 by the reprex package (v2.0.0)