Ademption pro tanto by testator's receipt of part of entire thing specifically bequeathed

The receipt by the testator of a pat of an entire thing specifically bequeathed shall operate as an ademption of the legacy to the extent of the sum so received. A bequeaths to B "the debt due to me by C". The debt amounts to 10,000 Taka. C pays to A 5,000 Taka the one-half of the debt. The legacy is revoked by ademption, so far as regards the 5,000 Taka received by A.