4. An upside-down mortgage is most likely to occur when _________. (a) market rates of interest plummet (b) real estate prices plummet (c) a local area loses major sources of employment (d) both (b) and (c) (e) underwriting guidelines are eased (f) none of the above 5. The market approach weighs most heavily in a residential appraisal because ________. (a) it is impossible to know the true cost of an older dwelling (b) the income approach cannot include the revenues generated by illegally rented basements (c) the income approach always underestimates rents paid in cash (d) the market approach can be manipulated by adjusting the radius of the market (e) most one family houses are owner-occupied, not rented for income (f) none of the above