Subbing for fresh lemongrass

Making a coconut beef curry today and the well-reviewed recipe I'm using calls for a stalk of lemongrass, which isn't available near me. Would you:

a) Use lemongrass paste (sometimes these pastes seem to really lack freshness)

b) Use lemon zest (fresh, but not exactly lemongrass)

c) Drive an additional ten minutes to get fresh lemongrass (my regular grocery is already a 15-minute drive)

The fate of my curry rests in your hands, internet strangers! TIA!