RC Oscillators: relationship of frequency to R, C

My textbook asks: "In what type of oscillator will a change by a factor of ten in resistor values NOT result in a frequency change by a factor of ten?  Choices: (a) Wien bridge; (b) Phase-shift; (c) Twin-T

My attempts at solving consisted of constructing each of these circuits on a breadboard and replacing the resistors and capacitors with different values of same.  In each case, the frequency change was inversely proportional to the values of R and C.

All my research states the same theory. 

Please provide guidance.  I have no electronics background and am teaching myself via a self-paced course. 

On 10/25 you responded to my ? ( In what typ of oscillator will a change by a factor of 10 in resistor values not result in frequency change by a factor of 10 . ..  Wein bridge, phase-shift or twin-t)

I wrote to the instructor asking if the textbook could be in error.  they responded: "To answer this question, you need to examine the formula for frequency for each oscillator type.  Each formula will contain a resistance term.  Observe which of the formulas is similar and which is different.  In addition, a change by a factor of 10 can be representedby multiplication 10 or by 1/10"

So, evidently, the correct answer would be the "phase shift".  Just wanted to let you know since you were kind enough to respond to my inquiry.