微观经济学问题（英文）

微观经济学问题（英文）
有两道经济题,英语的,题目没看懂.很弱.请帮放解释一下,当然,有答案最好啦.
1.Using indifference curve analysis, you can identify the point at which a consumer maximizes utility where the slope of the:
a.indifference curve is -1
b.budget constraint line is -1
c.indifference curve is equal to the slope of the budget constraint.
d.indifference curve is greater than the slope of the budget constraint
2.Economic reasoning would argue that there is an opportunity cost to:
a.all choices
b.more choices
c.only choices that involve money
d.only choives that do not involve money
没看懂什么意思. 也不知道题目对不对,也不知道是多选还是单选.懂的同学请帮帮忙啦.