Read the following context and choose the best option to answer the question.
Context: I soldered together an oscillator from a 555 chip this afternoon and it pretty much works . It 's got a Control Voltage input , an output and a big old 1meg pot for pitch control . The switch turns it on and off . It " pretty much works " in that it definitely puts out a loud square wave , but the pitch only goes up and down so much before cutting out , despite there being throw left on the dial ( about 1/5 of a turn in either direction ) .
Question: What may I be working on ?
Options: 
A. A complex electrical thing .
B. A bicycle .
C. A car .
D. A boat .


A