Final answer:
The shortest single bond in nitroglycerin is likely the O-N bond due to the resonance in the nitrate group, which gives it characteristics of a one-and-a-half bond.
Step-by-step explanation:
The question asks which single bond present in nitroglycerin is most likely the shortest. Among the options given, C-H, C-O, C-C, and O-N, the O-N bond is most likely to be the shortest. This is because nitroglycerin contains the nitrate group (NO3), which, due to the effect of resonance and the double bond character in each of the N-O bonds, leads to shorter bond lengths than a typical single bond. When comparing bond lengths, we can consider that a double bond between two atoms is shorter than a single bond between the same two atoms. As indicated by resonance structures, the nitrate group exhibits characteristics of one-and-a-half bonds rather than simple single bonds between the nitrogen and oxygen atoms, hence making these bonds shorter and stronger.