Concept: The question tests on the basic understanding in Algebra.
St(1):- Only gives information about r and nothing
St(2):-R can be +2 or a -2 and then the distance from t would be 4 which is r^2 (=>multiple values of t for same statement=>Insufficient)
Combining both,
|r-t| = r^2
=> r-t = r^2 or r-t = - (r^2)
=>t = r - r^2 or t = r + (r^2)
lets take r = -1/2
=> r^2 = 1/4
=> t = (-1/2) - (1/4) = -(3/4) or t = (-1/2) + (1/4) = -(1/4)
(Sufficient)
(option c)