Which of the following statements are true? select all that apply

a. < 2 and < 3 form a linear pair
b. < 1 and < 4 are supplementary angles
c. m< 1 + m< 2 + m< 3 = 180
d. m< 3 + m< 4 = m< +m < 2
e. < 1 and < 4 are vertical angles