How Did Hume Cast Doubt on Scientific Certainty and the Cause

How did Hume cast doubt on scientific certainty and the cause and effect theory?

A) He claimed that regularities observed in the past will happen in the present and future.
B) An objective reality exists which rational creatures can comprehend.
C) There is no law at work in nature that guarantees a specific cause will always produce a specific effect.
D) The mind has the ability to sense natural laws.
E) Science is able to prove a necessary connection that produces scientific laws of cause and effect.