If there were an ideal NMR experiment for an unknown compound, many organic chemists would consider a 2D 13C-13C 1,1-INADEQUATE (Incredible Natural Abundance DoublE QUAntum Transfer Experiment) to be it. The advantage of this experiment is the 1Jcc interaction that directly correlates a C atom to an adjacent C. The drawback is the long acquisition time required due to the low natural abundance of the 13C isotope at ~1.07 %.
For an unknown compound, the 13C-13C 1,1-INADEQUATE spectrum below shows 10 carbon atoms labeled C1 to C10. The pink lines connect the adjacent C atoms. Based on the spectrum, how many terminal carbon atoms are present?