Suppose all six equal-length strings of an acoustic guitar are played without fingering, that is, without being pressed down at any frets. what quantities are the same for all six strings? choose all correct answers.

In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second (1,126 ft/s). 

A, B, C and D are different because you get different pitches. 

The sound emitted by each string is traveling through the same medium (the air) and the speed of sound through the air is a constant. 

B is incorrect. Since speed of sound through the air is a constant; 

Ididn't get that much information but i did get that they got the assembly line idea from henry ford and they used it to make records!