Mathbug

$\dot{\overrightarrow{B}}=\mathrm{X}$ using mathrm. This function is special, it does not need brackets ({}) around the argument, while the other functions do.

$\dot{\overrightarrow{B}}=\text{X}$ using text.

$\dot{\overrightarrow{B}}=\text{X}$ using mbox.