The correct answer is C. Both 1 and 2.
An indifference curve is a graph that shows all the combinations of goods that a consumer is indifferent between. In other words, all the points on an indifference curve represent bundles of goods that give the consumer the same level of satisfaction.
Indifference curves always slope downwards to the right, because consumers always prefer to have more of both goods. If a consumer is indifferent between two bundles, and one bundle has more of one good and less of the other good, then the consumer must prefer the bundle with more of both goods.
Indifference curves can never intersect each other, because if they did, it would mean that the consumer is indifferent between two bundles that have different amounts of at least one good. This is not possible, because consumers always prefer to have more of a good, rather than less.
Here is a diagram of an indifference curve:
The indifference curve is downward-sloping, and it does not intersect itself.