Set up

a <- c(-1,1)
b <- c(-1,-1,1,1)
c <- c(-1,-1,-1,-1,1,1,1,1)

A <- c(rep(a,8))
B <- c(rep(b,4))
C <- c(rep(c,2))
D <- c(rep(-1,8),rep(1,8))

obs<- c(12,18,13,20,17,25,15,25,10,24,13,24,19,21,17,23)

library(DoE.base)
## Warning: package 'DoE.base' was built under R version 4.1.3
## Loading required package: grid
## Loading required package: conf.design
## Registered S3 method overwritten by 'DoE.base':
##   method           from       
##   factorize.factor conf.design
## 
## Attaching package: 'DoE.base'
## The following objects are masked from 'package:stats':
## 
##     aov, lm
## The following object is masked from 'package:graphics':
## 
##     plot.design
## The following object is masked from 'package:base':
## 
##     lengths

Part A Half-normal

mod <- lm(obs ~A*B*C*D)
halfnormal(mod)
## 
## Significant effects (alpha=0.05, Lenth method):
## [1] A     C     A:C:D

From the half normal plot it appears that the Main effects of A and C are significant. While the ACD interaction is also significant.