How many electron pairs does carbon share in order to complete its valence shell?

Me with these questions if you’re it sure don’t answer

Which of the following is a testable hypotheses?

Prior knowledge can be gained from personal experience and a) forming well-developed hypotheses. b) listening to opinions of other people on a topic. c) researching previous experiments and results on a topic. eliminate d) no other methods. it can only be gained by personal experience.