Use the following information for questions $7-10$:

Arlington Company is constructing a building. Construction began on January $1$ and was$-$completed on December $31.$ Expenditures were $$6,400,000$ on March $1,$ $$5,280,000$ on June $1,$ and $$8,000,000$ on December $31.$ Aflington Company borrowed $$3,200,000$ on January $1$ on a $5-$year, $12\%$ note to help finance construction of the building. In addition, the company had outstanding all year a $10\%,3-$year, $$6,400,000$ note payable and an $11\%,4-$year, $$12,000,000$ note payable.

$7.$ What are the weighted$-$average accumulated expenditures?

a$.$ $$11,680,000$

b$.$ $$8,413,333$

c$.$ $$19,680,000$

$8.$ What is the weighted$-$average interest rate used for interest capitalization purposes?

a$.11\%$

b$.10\mathrm{.}85\%$

c$.10\mathrm{.}5\%$

d$.10\mathrm{.}65\%$