Fill in the blank with the most appropriate option:

Ravi had to drop his plan of going to the picnic as he had certain _______ to meet during that period. 

Commitments 

The most appropriate word to fill in the blank is commitments.

The sentence means that Ravi had to cancel his plans for the picnic because he had certain obligations that he had to fulfill during that time. The word commitments refers to promises or obligations that one has made to others. In this context, it means that Ravi had made a promise to someone or to himself that he would fulfill certain obligations during that time, and he could not break that promise.

The other words do not fit the blank as well.

• Preparations refers to the actions that one takes in order to get ready for something.
• Observations refers to the act of watching and noting something.
• Urgencies refers to things that need to be done immediately.