Final answer:
The provided information lacks context and a clear connection to the measure of ∑B, making it impossible to accurately determine its value and select the correct measure from the provided options.
Step-by-step explanation:
To find the measure of ∑B, we are provided with a series of mathematical findings from the information given. However, the provided numbers and equations do not immediately give a clear answer for ∑B, and it seems that there is lacking context or additional information to directly calculate ∑B. A possible clue is an equation showing the doubling of an angle and the subtraction from another angle, but without the context of how these angles relate to ∑B, we cannot confidently select the correct answer. It is important when providing solutions to have a clear understanding of the relationships between provided angles and the one that we are expected to solve for. Without additional information linking these findings to ∑B, it is not possible to confidently complete this exercise and select the correct measure for ∑B from the options given