If deletion of a control element causes a decrease in gene expression, what must be the normal role of that control element?

a. to repress gene expression; the level of gene expression increases because repressors are not able to bind to the enhancer without the control element.
b. to activate gene expression; the level of gene expression increases because repressors are not able to bind to the enhancer without the control element.
c. to repress gene expression; the level of gene expression decreases because activators are not able to bind to the enhancer without the control element.
d. to activate gene expression; the level of gene expression decreases because activators are not able to bind to the control element.