x= 2/5

Required buckets= 25/(2/5) = (25×5)/2 = 62.5

Let's assume the capacity of each bucket is 'x'. 

- Therefore, the capacity of 25 buckets will be 25x. 

- Now, the capacity of the bucket is reduced to two-fifth of its present, so the new capacity of the bucket will be (2/5)x. 

To find the new number of buckets required to fill the tank, 

we can use the formula: New number of buckets = Tank capacity / Capacity of each bucket 

- The tank capacity remains the same, so it is still 25x. 

- The capacity of each bucket is now (2/5)x. Therefore, the new number of buckets required will be: 

New number of buckets = 25x / (2/5)x = (25x * 5/2x) = 62.5 

Therefore, 62.5 buckets of water will be required to fill the same tank with the reduced capacity bucket. Hence, the correct answer is option (c) 62.5.