In the following question, out of the four alternatives, select the alternative which will improve the bracketed part of the sentence. In case no improvement is needed, select "no improvement".
By now that garden (had been reduced) to an insignificant muddy patch.
The mean score in a test of the 10 boys in a class was 15 while the overall mean of the 25 students in the class was 16.2. What was the mean score of the girls?