B
1) Firstly, we need to orderly write this sequence of numbers:
![15,20,50,60,75,85](https://img.qammunity.org/2023/formulas/mathematics/college/t3c7xwofeoqzdiqvs8q5dfizpr86jcrcnt.png)
2) Then we need to calculate the Range of this Data Set, by subtracting from the highest values the least one:
![R=85-15=70](https://img.qammunity.org/2023/formulas/mathematics/college/idvo9u23rrd6g315vmxoexm72a2l0nv0rf.png)
2.2) The Midrange is the average between the Highest Value and the Least value on this Data Set:
![M=(85+15)/(2)=50](https://img.qammunity.org/2023/formulas/mathematics/college/t7c2yhm9wh26i2cihfn2vwmchdm9jlgxis.png)
3) Thus the answer is B