The only sentence among these which is used in the passive voice is A) The tree was planted by Mary.
The other options use the active voice.
(b) - listening.
(c) - looking back.
(b) - invited.
(a) - are looking forward to visiting.
This is an opinion oriented question, just use your imagination. No one can "Answer" this for you.
Be polite and respond by saying that making sure someone has a smile on their face doesn't cost anything and that everyone should stick together through tough situations and through good times .
Answer:
Why does the Cricket's song sound like the Grasshopper? Answer: When one is feeling sleepy on a winter night the Cricket's songs sound like the Grasshopper as we are not very alert and it becomes difficult to differentiate between the two sounds.