Which line's meter is iambic? A.) At the end of the month, I get paid.

B.) I give the best of all I have to offer Sam.

C.) Quarterly figures are plummeting steadily.

D.) Stopping smoking helps your health.

I believe the line whose meter is iambic is:

B) I give the best of all I have to offer Sam.

Explanation:

We can define iamb a a sequence consisting of an unstressed syllable followed by a stressed one. Therefore, if we highlight the stressed syllable in each line, we will be able to verify which one is iambic:

A) At the end of the month, I get paid.

B) I give the best of all I have to offer Sam.

C) Quarterly figures are plummeting steadily.

D) Stopping smoking helps your health.

All lines present a certain rhythm. But the only one whose rhythm is determined by a pattern of unstressed-stressed (iamb) is line B:

I give the best of all I have to offer Sam.

i have a basic answer but if you want a more in depth