Fill in the blanks with the most appropriate option:-

As the Mahindra dived off the springboard, he was____________to see that the water had been drained off the pool night before.

horrified

The correct option to fill in the blanks is horrified.

The word "horrified" is an adjective that means "filled with horror or shock". It is the most appropriate word to use in this context, as it describes the speaker's reaction to seeing that the water had been drained off the pool.

The other options are not as appropriate:

• Horrifying is an adjective that means "causing horror or shock". It is not as appropriate as "horrified", as it does not convey the same sense of personal experience or reaction.
• Horrifies is the third person singular present tense of the verb "to horrify". It is not as appropriate as "horrified", as it does not convey the same sense of immediacy or surprise.
• Horrify is the verb "to cause horror or shock". It is not as appropriate as "horrified", as it does not convey the same sense of being in a state of horror or shock.