P inc. has a variable overhead rate variance of $4,000 u, a variable overhead efficiency variance of $1,500 f, a fixed overhead budget variance of $2,000 f and a fixed overhead volume variance of $10,000 u. From the information, it can be determined that overhead was______.
a-overapplied
b-neither underapplied
c- nor overapplied
d- underapplied