Answer: Lindsey’s inventions are much safer than Edward’s.
In this sentence, the items that are being compared are Lindsey's inventions and Edward's inventions. However, as the second part is repetitive and it is easy to imply its purpose, the word "inventions" can be omitted. However, for the sentence to be clear, the possessive has to be maintained. Therefore, the correct way of writing the second party of the sentence would be "Edward's."
The correct answer should be Lindsey's inventions are much safer than Edward's, because the word omitted due to word economy is Edward's (inventions). Other sentences provide somewhat nonsensical comparisons, but with given context might be correct.
