Ritika decided to get up early (1)/ to wear a nice dress (2)/ and visit her aunt. (3)/ No Error (4).
What is the error in above sentence? My book says (2) is wrong, but I didn't understand.
I don't see anything grammatically wrong with the sentence. But there is a logic problem. When the word "to" is used in a construction like this, it means "for the purpose of" or "making possible". So the sentence is saying that Ritika got up early so that she would be able to wear a nice dress, or that she got up early because she wanted to wear a nice dress. It is difficult to see how getting up early is necessary to be able to wear a nice dress.
A better sentence would be, "Ritika decided to get up early and wear a nice dress to visit her aunt."