The two most abundant isotopes of boron are 10b and 11b, with 11b being about 4 times more abundant. in the mass spectrum of trimethylborate [(ch3o)3b], a. the peak at m/z 103 has an intensity which is 1/4 the intensity of the peak at m/z 104 b. the peaks at m/z 103 and m/z 104 have equivalent intensities c. the peak at m/z 103 has an intensity which is 4 times that of the m/z 104 peak d. none of the above