Data Science : Python, Java or C ?

It is commonly believed that Data Scientists need to learn Python and R to be good at machine learning, AI, IOT, and data management. However, as languages and methods change all the time in computer science, this should not be considered the case. Since C runs faster because it is a low level language, we don't really know if data scientists will need to C in the future. Below is a chart from the internet( sorry no source) that examines combinations of computer programming languages, machine learning and data science with respect to job posting.