What are the several parameter setting methods for Spark applications? (multiple choices)

What are the several parameter setting methods for Spark applications? (multiple choices)
A . Configure in the application configuration file spark-defaults.conf
B . When submitting the application, set it through –conf
C . In the application code, set by the setProperty method of SparkContext
D . In the application code, set through the SparkConf object

Answer: ABD