The H.C.F is always  

H.C.F of $10,15$  is $5$

L.C.M of $10,15$  is $5\times 2\times 3=30$

Option (A): 5 (H.C.F) is not multiple of 30(L.C.M)

Option (B): 5 (H.C.F)is factor of 30(L.C.M)

Option (C): 5 (H.C.F)is not divisible by 30(L.C.M)

Hence $‘\text{B}’$  is correct answer.