Which sentence from this passage has inadequate support for its main idea? A) Flowering plant, when eaten by pets, can also be lethal. B) Pets can chew and swallow seemingly safe things, resulting in disaster. C) There are many other common household items that are hazardous to pets. D) It may seem perfectly harmless to toss a pet a grape or a raisin as a treat, but these can be very deadly.

C) There are many other common household items that are hazardous to pets.

Explanation:

This is the text "Pet Dangers" by Carole Jenkins.

The main focus of the article is to state that homes should be "pet-proof" just as they are "child-proof".

She then continues to state all the possible dangers to pets, most of which don't seem so obvious.

After introducing us to potential outcome of pets' chewing and ingesting of some of the seemingly safe things (a grape, a raisin, a flowering plant etc.), she concludes that there are many other common household items hazardous to pets.

However she doesn't name these items or explore this theme a little furthet, making this sentence excessive and "out of sync" with the article's main idea.