Given the logic program and the goal as below

Logic program

f$([],0).$

f$([$XIY$],$ S$)$ :$-$ f$($Y$,$ S$1),$ S is X $+$ S$1.$

Query

$?\_$ f$([1,2,3,4,5],$ S$).$

What is the output?

Question $7$ Answer

a$.$

S$=5$

b$.$

S$=1$

c$.$

S$=6$

d$.$

S$=15$