To determine the measure of angle \( m∠7 \), we need to use the information given about \( m∠6 = 140° \).
Assuming that angles 6 and 7 are supplementary (which means they add up to 180°), we can set up the equation:
\[ m∠6 + m∠7 = 180° \]
Substituting \( m∠6 \) into the equation:
\[ 140° + m∠7 = 180° \]
Now, subtract \( 140° \) from both sides:
\[ m∠7 = 180° - 140° \]
\[ m∠7 = 40° \]
Therefore, \( m∠7 \) is \( 40° \). The correct response is 40°.