To find the equation that represents the situation, we start with the current number of weeds, which is 250. Grandma will be removing weeds at a rate of 5 per minute, so after \( m \) minutes, the number of weeds removed would be \( 5m \).
We want to know how long it will take for the number of weeds to go from 250 to 30. This gives us the equation:
\[ 250 - 5m = 30 \]
So, the correct choice is:
D. 250 - 5m = 30