Shouldn't it be हैं not है?
why is तुझे केले पसंद हो wrong?
well you said ho instead of hai
is hai always used with pasand?
It's not, but hona here has to agree with kele, so it's hain.
Is the हैं required? It marked the answer as wrong without it
Yes, without it and literally translated you'd saying something like 'to you bananas pleasing'. You need हैं here in Hindi just like you need 'are' in the English.
What is the difference between 'tumhe', and 'tum'
Tumhe means ‘to you’ and tum means ‘you’
So tum will also be right?
तुम is not right in this sentence because in Hindi one says literally To you bananas are appealing, that is, bananas is the subject, while you is the object. Therefore, the object form तुम्हें should be used.
What is the difference here between tumhain and tujhe? Isn't it mujhe kele pasand hain?
तुम्हें is to you (comes from तुम) which is more respectful then तुझे ( from तु) youb can use either
मुझे is to me