How do scientists confirm their conclusions when they use the scientific method? they assert a belief. they repeat their work. they gather data. they state their problem

Scientists use  observations and data  to  draw a  conclusion. observations lead  to  the recording of data.  scientists  ask questions about  their  observations and then collect data  to  answer  their  questions, then  they  have  their  evidence.

These are my options 

a.they gather data.

b.they assert a belief.

c.they repeat their work.

d.they state their problem.