Yes a cat can get jealous. PetMD is a reliable source. The claim coming from this source/ someone citing this source in their clam is supported. I looked into the claim further and came across Psychology Today. This cite going into depth about how cats can feel deeper emotions especially towards their owners and jealousy is one of them. Psychology Today is also a reliable source because it is written by Doctor Karen Wu who is a professor of psychology at California State University.
https://www.psychologytoday.com/us/blog/the-modern-heart/202202/do-cats-get-jealous