
Answer:
Hello your question is incomplete attached below is the complete question
answer: RS = ST ( option b )
Step-by-step explanation:
First we consider Î SCA and Î TCB
â SCA  = â TCB  ,  â CAS = â CBT = 90°
if we assume  RS = ST then ÎSRT will be termed an Isosceles triangle with its legs : SR = ST. also vertex S bisects the base of the triangle.
Î SBR â ÎSBT Â from here we can deduce that ; BR = BT
From the assumptions what is actually missing to contrast the proof is : RS = ST