What Is the Difference Between Major Depressive Disorder and Bipolar

What is the difference between major depressive disorder and bipolar disorder?

A) Major depressive disorder is genetic and bipolar disorder is acquired.
B) Major depressive disorder is found equally in men and women and bipolar disorder is predominantly found in women.
C) Major depressive disorder is caused by a chemical imbalance and bipolar disorder is caused by a structural problem in the brain.
D) Major depressive disorder involves a depressive state and bipolar involves periods of mania alternating with depression.