Answer:
Richa had worked very hard today.
Step-by-step explanation:
Past perfect is the past version of present perfect. The present perfect tense is used to describe things that have passed not long ago and are considered to be in the near past and not in the past. The line's a little blurry, but just know the present perfect tense is usually used as "has been", the present tense of the verb and the perfect or passive tense of the auxillary. Another example would be "has worked".
Since the past perfect tense is the past version of the present perfect tense, "has been", as an example would be "had been" in the past perfect tense, and "has worked" would be "had worked". Hence, the answer is "Richa had worked very hard today."
Hope this helped!