In the sports academy, the total number of people $n(U)=300$
Number of people who play only cricket $n(C)=105$
Number of people who play only hockey $n(H)=70$
Number of people who play only football $n(F)=50$
Number of people, who play both cricket and hockey $n(C\cap H)=25$
Number of people, who play both hockey and football $n(H\cap F)=15$
Number of people, who play both cricket and football $n(C\cap F)=30$
The number of people who play only one sport $n(C)+n(H)+n(F)=105+70+50=225$
The number of people, who pay at least two sport $($it mean the total number of people $-$ the number of people who play only one sport$)=300-225=75$ $($at least two sports means two or more sports$)$
Percentage $=\dfrac{75}{300}\times 100=25\%$
So,correct answer is $(B).$