Below is a simplified grammar for specifying expressions

$E(E)|T+E|T-E|T|$

$TF**T|\frac{F}{T}|F$

$F|d|(E)$

$ld$ letter $|$ letter $ld|$

letter $a|b|c|d|e|f|g|h|i|j|k|1|m|n|0|p|q|r|s|t|u$

$|v|w|x|y|z|$

This grammar doesn't allow for unary minus, for example $-$x$.$ Suppose to fix this omission the production $E-E$ is added.

Which of the following can be generated?

$-x-y$

$x^{**}y=-x^{**}-y$

$-x**-y$

$x^{**}y-x^{**}-y$