Right option is (a) 35

The best I can explain: In Jodhpur mini compaction test, a 2.5 kg DRT is used which falls freely from a height of 25 cm. The height of free fall in Abbot compaction test is 35 cm above the base. For the Standard Proctor test, the height of free fall is 31 cm and for Modified Proctor test, the height of free fall is 45.72 cm.