A Vector $\overrightarrow { \mathrm { A } }$ Is Added To

Multiple Choice

A vector $\overrightarrow { \mathrm { A } }$ is added to $\overrightarrow { \mathbf { B } } = 6 \hat { \mathbf { i } } - 8 \hat { \mathbf { j } }$ .The resultant vector is in the positive x direction and has a magnitude equal to $\overrightarrow { \mathrm { A } }$ .What is the magnitude of $\overrightarrow { \mathrm { A } }$ ?

A) 11
B) 5.1
C) 7.1
D) 8.3
E) 12.2