Two sides of a triangle are 9 cm and 12 cm long. What is the range of possible lengths for the third side?
Select one:
a. 2 cm < x < 24 cm
b. 2 cm < x < 21 cm
c. 2 cm < x < 18 cm
d. 3 cm < x < 21 cm
e. 3 cm < x < 18 cm
f. 6 cm < x < 24 cm
g. 6 cm < x < 21 cm