Required Bandwidth for ASK
The bandwidth doesn't start at DC (0 Hz), but is centered around your carrier frequency, so  


  \$ f_{MIN} = f_C - BW/2 = 15Hz - 5Hz = 10Hz\$, and
  \$ f_{MAX} = f_C + BW/2 = 15Hz + 5Hz = 20Hz \$  


or 


  \$ BW = f_{MAX} - f_{MIN} = 20Hz - 10Hz = 10Hz \$


The minimum bandwidth for ASK is equal to the Baud rate (which in this case = bit rate).

Also, IIRC, d can be a value in [0..1], so isn't restricted to 0 or 1.