To solve for the measure of ∠D, we start by analyzing the information given.
- We know that m∠B = 58°.
- The sum of m∠E and m∠D is given as 121°: \[ m∠E + m∠D = 121° \]
Since m∠B and m∠E are vertically opposite angles, they are equal. Therefore: \[ m∠E = m∠B = 58° \]
Now, we can substitute m∠E into the equation to find m∠D: \[ 58° + m∠D = 121° \]
To find m∠D, we can rearrange this equation: \[ m∠D = 121° - 58° \] \[ m∠D = 63° \]
Thus, the measure of ∠D is: \[ \boxed{63} \]
So the correct response is 63 degrees.