If You Confine an Electron to a Box and Know $65 \mathrm {~m} / \mathrm { s }$

If you confine an electron to a box and know that the uncertainty in the electron's speed is $65 \mathrm {~m} / \mathrm { s }$ , what is the smallest length that the box could have? (melectron $= 9.11 \times 10 ^ { - 31 } \mathrm {~kg} , h = 6.626 \times 10 ^ { - 34 }$ J.s)

A) $1.8 \times 10 ^ { - 5 } \mathrm {~m}$
B) $8.4 \times 10 ^ { - 6 } \mathrm {~m}$
C) $1.1 \times 10 ^ { - 5 } \mathrm {~m}$
D) $5.8 \times 10 ^ { - 6 } \mathrm {~m}$
E) $1.8 \times 10 ^ { - 6 } \mathrm {~m}$