In the example below, how does the difference between the character's spoken words and internal thoughts affect the story?

"welcome back! " i said. "it's great to see you again! " i'm about to go on, but then i think: shut your mouth. stop being nice. i'm seeing spots. no, i'm dizzy. this is what they call passing out. don't do that. don't pass out. don't fall. stay upright stay awake.
a. it foreshadows events that will affect the character in the future.
b. it creates a sense of tension between what the character says and thinks.
c. it changes the point of view from one character to another.
d. it introduces a new character who will have an impact on the plot.