A two digit number is 3 more than 3 times the sum of its digits. The tens digit is 6 less than the units digit, If t= the tens digit and u = the units digit, which system must be true?

A. t - u=6
10t + u =3t + u - 3

B. t = u - 6
10t + u = 3t + u - 3

C. t - u = 6
10t + u =3( t + u ) - 3

D. t = u - 6
10t + u = 3( t + u ) + 3