Explanation
The null hypothesis presumes the status quo. Andy is testing whether or not people who receive an electronic coupon spend more on average, so, the null hypothesis states that people who receive the coupon do spend more on average.

Since you are trying to determine whether sales increased above the current average of $8000, the population mean for the null hypothesis is $8000; whereas the mean for the alternative hypothesis is greater than $8000. Hypotheses are always stated in terms of population you are working with, ruling out options A and B.
The test is whether sales are higher than the average of $8000 per day, which rules out option C.

Explanation
ETL is a process that is used during data integration to collect, blend, and load data. ETL stands for extract, transform, and load, which are the three main steps involved in moving data from different sources to a common destination, such as a data warehouse or a data lake. ETL helps to consolidate and standardize data for analysis and reporting purposes. References: CompTIA Data+ Certification Exam Objectives, page 12