Identify the longest, shortest, strongest, and weakest bonds from those highlighted below.

Longest: D. Shortest: A. Strongest: A. Weakest: D.

Explanation: Answer choice A is the shortest and strongest. The greater number of bonds causes the electrons to be more compact and closer together. This makes the bond length short. Because the bond is tighter, it is also stronger.

Single bonds are the weakest and longest. So, now we must look at the difference between C and D. They're both C-C bonds, but the carbon bond in choice D is weaker because of the difference in p-character (hybridization).