Understanding the structure and stability of base pairing in DNA. Predicting relative melting temperature (Tm) for DNA fragments.

Two duplex (ie. double stranded) DNA fragments are shown below.  Under identical conditions (ie. ionic strength, buffer composition, temperature, etc.), which double-stranded fragment would denature at the lower temperature?

Fragment A:

5' A-A-G-T-A-G-T-T-T-C-A 3'
3' T-T-C-A-T-C-A-A-A-G-T 5'

Fragment B:

5' G-C-A-G-G-T-C-G-C-C-T 3'
3' C-G-T-C-C-A-G-C-G-G-A 5'