Guitar strings are tuned to 6 frequencies by selecting the string material's mass/length and adjusting the tension in the string. 1 (E) 329.63 Hz E4 2 (B) 246.94 Hz B3 3 (G) 196.00 Hz G3 4 (D) 146.83 Hz D3 5 (A) 110.00 Hz A2 6 (E) 82.41 Hz E2 On each string, the frequency of the played note is altered by depressing the string against a fret. Each fret changes the frequency by a factor of 21/12 such that with 12 of these steps the frequency is altered by 2. All but one string can create middle C by depressing the sting to end at a fret. Which string cannot make middle C, and which frets on the other strings do make it? Explain your work