The right answer is A.
Lǎobǎn, zhè shù huār duōshao qián?
Li Hua：老板， 这 束 花儿 多少 钱？
How much does this bunch of flowers cost?
Wǔshí kuài qián.
Seller：五十 块 钱。
Tài guì le!
Li Hua：太 贵 了！
That’s too expensive!
Nǐ xiǎng huā duōshao qián?
Seller：你 想 花 多少 钱？
How much do you want to spend?
Sānshí kuài qián.
Li Hua：三十 块 钱。
In the dialogue, the word 花 (huā) appears twice and both with different meanings. In the first sentence, “这束花儿多少钱？(Zhè shù huār duōshao qián?),” the word 花 (huā) is a noun meaning “flowers,” while in the second sentence, “你愿意花多少钱 (nǐ yuànyì huā duōshao qián),” it’s used as a verb meaning “to spend money on something.” As a verb, it can also be used to mean, “to spend time or energy doing something.”
As a noun:
Zhè shù huār hěn piàoliang!
这 束 花儿 很 漂亮！
This bunch of flowers is beautiful!
As a verb:
Bié huā tàiduō qián!
1. 别 花 太多 钱！
Don’t spend too much money!
Wǒ měitiān huā liǎngge xiǎoshí xuéxí hànyǔ.
2. 我 每天 花 两个 小时 学习 汉语。
I spend two hours every day studying Chinese.
The word 费(fèi) in B means “cost,” or “take.” It can be used as a noun or as a verb.
When it is used as noun, it means fee or charge.
eChineseLearning de xuéfèi hěn dī.
eChineseLearning 的 学费 很 低。
eChineseLearning’s fee is cheap.
When 费 (fèi) is used as a verb, it means “to cost,” or “to spend,” but usually is attached to a sense of wasting money, time or energy on something.
Duì bu qǐ, ràng nín fèixīn le.
对 不 起，让 您 费心 了。
I’m sorry for troubling you.
话 (huà), meaning “dialogue,” or “saying” and has nothing to do with “花 (huā)” or “费 (fèi).” Make sure to not get confused as it does have a similar pronunciation with “花 (huā).”