I would say b or c. Tbh if it was me answering I would go with c. Hope this helps!!
The sentence that contains a boldface infinitive is D. Lisa wants TO GO.
It is easy to spot an infinitive - it is usually a combination of the word TO plus a verb.
A and C are incorrect because those are not infinitives, but rather prepositional phrases. B is incorrect because it is an infinitival phrase, rather than a single infinitive.
Similes compare two things. Because clowns are considered by most to be very funny, the object would also have to be something funny.
Therefore you could say...
A clown is as funny as a medieval joker.
A clown is as funny as a cat barking like a dog.
A clown is as funny as a comedy movie.
I think its kind of inappropriate but not really. In a part the mom explains to our main character how babies are made but overall its pretty kid friendly.