Answer:
A.
Step-by-step explanation:
A. City voters were asked about candidates. That seems to be random.
B. A survey about singers took place at a specific concert. Naturally, the people who are there like this singer. It is not random.
C. Customers were asked about food at a pizza shop. Naturally, they like pizza. This is not random.
D. An email survey was sent. Mostly people who own computers will respond. This is not random.
Answer: A.
