Correct answer its letter A
I think you mean nullification. It was the idea that individual states could nullify federal laws if they felt like it.
Engineers will often use reverse-engineering to solve problems. For example, by taking things apart to determine an issue, finding a solution and then putting the object back together again. Engineers know how things work, and so they constantly analyse things and discover how they work.
The following sentence is a run-on: The Merchant of Venice is an interesting play it is about a young man named Bassanio, who falls in love with wealthy girl, Portia.
It should be re-written the following way:
The Merchant of Venice is an interesting play. It is about a young man named Bassanio, who falls in love with wealthy girl, Portia.
The sentence is two sentences fused together as one, which makes it a run-on and also difficult to read. When the proper punctuation is used the sentence is no longer a run-on and is then easier to comprehend.