What is the value of s$1$ after the code that follows is executed?

StringBuilder s$1=$ new StringBuilder$()$;

s$1.$append$("115-88-9525")$;

s$1.$deleteCharAt$(4)$;

Question $8$ options:

a$)$

$115-88-9525$

b$)$

$115-8-9525$

c$)$

$115889525$

d$)$

$11588-9525$