Eric has a mutual fund portfolio including $50\%$ stocks, $40\%$ bonds, and $10\%$ cash. Stocks have $7\%$ return, bonds $-4\%,$ and cash $1\%.$ What is his portfolio's weighted average return?

$4\mathrm{.}7\%$

$2\mathrm{.}0\%$

$5\mathrm{.}2\%$

$3\mathrm{.}9\%$