Can someone help with this

Point e(−5, 3) and point d(−4, −3) are located on the grid. which measurement is closest to the distance between point e and point d in units? a) 6.1 units b) 6.3 units c) 6.5 units d) 6.7 units

Which one ? is the answer and how to find this answer

Combine like terms to make a simpler expression 3z+z