How many compounding periods are there in an investment shown below?

$\backslash$table$[[$Principal$,\backslash$table$[[$Rate of Compound$],[$Interest per Year$]],$Compounding Period,Time$],[$$$6000,2\mathrm{.}4\%,$Quarterly,$7$ years$]]$

a$.7$

c$.28$

b$.84$

d$.4$