From the sine law we have that:

from the first part of the equality, we obtain:

since sin(17)/sin(71) is less that 1, we conclude that RT is longer than SR
Now, comparing SR and ST with the equalities, we have that:

Then ST is longer than SR, now we need to compare ST AND RT

Then ST is longer Than RT, we conclude that ST is longer than RT which is longer than SR then the correct option is the SECOND ONE (RS,TR,ST)