Which of these transition words completes the sentence showing a contrast?

christi will not join the chorus, the director has extended a personal invitation.

a) since

b) except

c) whereas

d) although

where is the drop down menu and where are the answers

a constant variable, normally called a controlled variable, is the term for a variable that remains constant throughout an experiment, though other variables may change. an example is the water pressure for a faucet when measuring the amount of water released when the faucet is opened to various increments.