During $2018Z$ Ltd$.$ incurred a net loss of $$50,000$ and issued $$10,000$ of common shares. On the company's balance sheet as at December $31,2018ZLtd.$ showed total assets of $$150,000$ and a retained earnings balance of $$60,000.$ Which of the following statements is true if total liabilities decreased by $$20,000$ during $2018?$

$($a$)$ Total assets at the end of $2017$ were $$210,000.$

$($b$)$ Total assets at the end of $2017$ were $$90,000.$

$($c$)$ Total assets at the end of $2017$ were $$150,000.$

$($d$)$ Total assets at the end of $2017$ were $$60,000.$