Hi all. I am learning simplifying relative clauses and have created some sentences below. Please help me to check them

1a.Computer is a machine which is able to transfer electric signals.
1b.Computer is a machine able to transfer electric signals.
2a.Instrumental music is a genre of music that makes people feel relaxed.
2b.Instrumental music is a genre of music making people feel relaxed. (I am doubt this is correct as it sounds weird to me...)
3a.The person who is riding a bicycle over there is my cousin.
3b.The person riding a bicycle over there is my cousin.
4a.Mobile phone is an electronic device which is initially designed to merely facilitate people's communication, and now it has so many functions.
4b.Mobile phone is an electronic device initially designed to merely facilitate people's communication, and now it has so many functions.
5a.The guy who was murdered last night was his father.
5b.The guy murdered last night was his father.
Thank you indeed.