Recall from Conceptual Connection 2.7 that carbon has two naturally occurring isotopes: C-12 (natural abundance is 98.93%; mass is 12.0000 amu) and C-13 (natural abundance is 1.07%; mass is 13.0034 amu). Without doing any calculations, determine which mass is closest to the atomic mass of carbon.

(a) 12.00 amu 

(b) 12.50 amu 

(c) 13.00 amu